Continuum arm robot system

Abstract

To provide a control system for a plurality of compliant robots to be joined.SOLUTION: A control system having an actuator pack of each compliant robot itself includes: individual local control systems which are associated with each actuator pack; and an overall control system which controls relative movement of individual local control systems and robots when the robots are close to each other in a work space, and in which an overall control signal provides a signal to an actuator associated to at least two compliant robots so as to induce linked motion of a continuum arm robot. In the control system, a clock of each individual control system is synchronized with other clocks, and a redundancy control system, which performs control for motion of the compliant robot within prescribed degrees of freedom so that motions of at least two compliant robots do not conflict, is provided.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a system of compliant robots that are linked. In particular, the present disclosure relates to a control system for a plurality of joined compliant robots.

Background Art

[0002] Continuum arms or snake arm robots are of increasing interest in several applications. This is because such robots can be operated in spaces that are not easily accessible to other robotic systems or human operators. This is due to the ability to manipulate the body with several degrees of freedom so that the end tool can be accurately and easily positioned. This positioning is controlled by actuators that manipulate tendons in the robot so that each joint of the arm can be individually controlled with a high degree of positional accuracy.

[0003] Most arm robots have 6 or fewer degrees of freedom. However, if the task requires a greater amount of dexterity, the number of degrees of freedom required is increased. In such cases, the number of degrees of freedom needs to be increased. This increase in the number of degrees of freedom means that the arm can operate in a limited area, for example, in the repair of complex structures or for use in minimally invasive surgery. Continuum arm robots are designed along two main lines. First, there are snake-type robots consisting of a plurality of rigid-link sections connected either by rigid R / U / S (rotational / articulated / spherical) joints or by compliant joints. Each section is composed of one or more pieces and is controlled independently of the others, either on-board or remotely actuated. Second, there are continuum robots consisting of a compliant backbone, the local and global deformations of which are controlled by one or more actuators.

[0004] Despite the functionality described above, there are current design challenges to highly compliant robots, stemming from the number of joints required in a robotic arm. As a result of these joints, robotic arms suffer from a lower degree of stiffness compared to conventional 6-degree-of-freedom robots. This reduced stiffness also results in reduced load capacity, limiting the interaction the arm can have with the environment in which it operates. Current technology aims to overcome this by "freezing" the system by locking actuators or by adding stiffening mechanisms to the backbone. While this may work for shorter robotic arms, when used with longer robots, the arm behaves like a long cantilever beam, and the beam's deflection causes significant positional and movement problems. This limits the use of such robots to light tasks due to the risk of damaging the robot and / or the object it is working on. Therefore, there is a need for improved continuous-arm robotic systems to overcome these problems. [Overview of the project] [Means for solving the problem]

[0005] According to a first aspect of this disclosure, a control system for a compliant robotic system including at least two compliant robots, wherein each compliant robot has its own actuator pack, and the control system is Individual local control systems associated with each actuator pack, each local control system providing control signals to actuators to cause movement within the associated compliant robot, A total control system for controlling the overall motion of robots when those robots are in close proximity in a workspace, wherein the total control signal provides signals to actuators associated with at least two compliant robots to cause linked motion of a continuum arm robot, A control system is provided in which each individual control system is provided with a clock, the clock of each individual control system is synchronized with other clocks, and the overall control system is provided with a redundant control system that restricts the motion of the compliant robots within a given degree of freedom so that the motion of at least two compliant robots does not conflict when operating under the overall control system.

[0006] At least one of the compliant arm robots may be provided with a clamping system for linking at least one of them to at least another compliant robot in the system, the mechanism of which the clamping system is controlled by either a local controller or a global controller associated with the arm to which the clamping system is provided.

[0007] The clamping system may be equipped with an interlocking device that, if disconnected, restricts the movement of the robot system and activates a redundant control system when connected.

[0008] A compliant robotic arm may be equipped with sensors that provide signals to both local controllers and the overall control system.

[0009] The local control system can be programmed by the kinematics model of each robot in motion, which is used to compensate the signals to the actuators when motion commands are input.

[0010] The overall control system may include kinematic models for all robots in the system, and models for the connected systems, which are used to compensate for the signals provided to actuators when motion commands are input.

[0011] Each local controller and the global controller may be located on a separate computer system, and the local controllers are linked to the global controller. Local and global controllers may be located on the same computer system.

[0012] The redundant control system can deactivate the required number of motion control actuators from one of the actuator packs. The redundant control system can deactivate the required number of motion control actuators from each of the actuator packs.

[0013] When the robots are in the correct position, the overall control system can place one or more of the compliant robots into an idle state, while at least one of the compliant robots remains active, allowing the operator to still control its movement.

[0014] When the robots are in the correct position, the overall control system can place one or more of the compliant robots into a passively controlled state, while at least one of the compliant robots remains active, allowing the operator to still control its movement. When the robot is in the correct position, the overall control unit can maintain all arms in an active state.

[0015] According to a second aspect of this disclosure, a method for controlling a plurality of compliant robots as described herein, The steps include inserting multiple compliant robots into the workspace, A step of manipulating the movement of a compliant robot using individual local control systems in order to move the compliant robot to a first desired position, The compliant robot, by being in a designated position, has its local control system suspended, and the overall control system, as part of the system, takes over the motion control of the compliant robot, performing the following steps: The steps involve using a compliant robotic system to perform a predetermined task, The steps include positioning the robot at a second desired location, The steps include disengaging the overall control system and re-engaging the local control system, The steps include removing the compliant robot from the workspace and A method is provided that includes this.

[0016] When the compliant robots are in a first desired position, they can be clamped together, and the clamps can be disengaged when the compliant robots are in a second desired position.

[0017] When the compliant robot is in the first desired position, a pre-programmed connection sequence can be activated, which provides automatic control for clamping the compliant robot as a whole.

[0018] When the compliant robots are in a second desired position, a separation sequence may be activated, which provides a means to automatically separate the robots and deactivate the overall control system.

[0019] When the compliant robots are clamped together, the overall control system can place at least one of the compliant robots in a idle state and at least one in an active state.

[0020] When compliant robots are clamped together, the overall control system can place at least one of the compliant robots in a passive state and at least one in an active state.

[0021] One skilled in the art will appreciate that, except when mutually exclusive, features described in relation to any one of the above aspects may be applied to any other aspect. Furthermore, except when mutually exclusive, any feature described herein may be applied to any aspect and / or combined with any other feature described herein. Embodiments will now be described by way of example only with reference to the figures.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1a is a diagram showing a prior art example of a cutaway internal view of a continuum arm robot. FIG. 1b is a diagram showing an example of a joint of a continuum arm robot. [Figure 2] It is a diagram showing the external shape of a continuum arm robot system according to the present disclosure. [Figure 3] It is a diagram showing a schematic view of the operation of a connected continuum arm robot according to the present disclosure. [Figure 4] FIG. 4a is a diagram showing an example of a control system used to control at least a two-arm continuum arm robotic system of the present disclosure. FIG. 4b is a diagram showing an example of a control system used to control at least a two-arm continuum arm robotic system of the present disclosure. [Figure 5] It is a diagram showing a flowchart of the operation of a linked continuum arm robotic system of the present disclosure. [Figure 6] It is a diagram showing an example of a three-continuum robot system according to the present disclosure. [Figure 7] It is a diagram showing an example of a clamping mechanism between a second continuum arm robot and a first continuum arm robot as shown in FIG. 6. [Figure 8] This figure shows an example of a control system including three robotic systems as disclosed herein. [Modes for carrying out the invention]

[0023] Aspects and embodiments of this disclosure will now be discussed with reference to the accompanying drawings. Further aspects and embodiments will be obvious to those skilled in the art.

[0024] Figure 1a shows a conventional example of a cross-section internal diagram of a continuum arm robot. The conventional continuum arm robot includes a continuum arm robot section 101 that is permanently integrated and extends outward from an actuator pack 102. The actuator pack 102 contains a number of independent actuators 103. These actuators are used to regulate the tension in tendons extending through the continuum arm 101. The tendons are associated with joints in the arm, and each of these joints is designed to move in response to the tension or relaxation of the tendon associated with the joint. This tension or relaxation of the tendon, therefore, causes the joint to contract or extend, which allows the continuum arm to bend. The actuator pack is shown to be positioned on a rail or support 104, positioned close to the components to be inspected. The actuators are further provided with a number of power and signal cables 105 used to power and address the actuators. Individual signals traversing the array of actuators result in joint control so that the continuum arm 101 can be directed. Figure 1 does not show the need for an operator with a computing device linked to the actuators in order to control the movement of the continuum arm and to perform the desired task. Since the continuum arm is permanently integrated into the actuator pack, if different equipment is required, it will require the use of a complete continuum arm robotic system including the actuators. The computing device connected to the conventional actuators may be any suitable computing system, such as a laptop computer, featuring essential operating software for the robot that enables the continuum arm to be controlled, and control inputs such as joysticks.

[0025] Figure 1B shows an example of a continuum robotic arm joint. The arm contains multiple joints, each requiring at least two cables. For example, a system with three joints, each having four tendons, would require 12 actuators to drive them. Increasing the number of joints requires increasing the number of actuators, or otherwise reducing the number of tendons per joint. The highlighted joints 106, 107, and 108 are capable of being manipulated to move in three dimensions. The joints are configured such that joints 106 and 108 can bend in the same plane relative to the center of the arm, while the plane in which joint 107 can move is shifted by 90° relative to joints 106 and 108. It is through a thoroughly alternating joint angle configuration, each of which results in movement in a different orthogonal plane, that the arm can be manipulated in three dimensions. Each joint in the arm has a limit to the amount it can bend, and this limit is determined by the design of the arm and the materials used. This includes the flexion limit at each joint, collective characteristics such as the minimum bending radius, and the amount of torque required to cause the resulting change within the joint. The presence of space within the joints allows the joints to move and the ease of movement of the joints, which results in the lower rigidity of the arm compared to other robotic arms of the same length. This is because the structural behavior of a snake-type robotic manipulator can be likened to a cantilever beam under load, since the system is fixed at one end to a base with an actuation pack, and the rest of the arm is used to move through the environment without other points of contact. In this situation, any load applied to the body and / or end of the snake-type robot, including the weight of the snake-type robot itself, will cause significant deflection from its ideal position. At the end of the arm, an instrument or probe is positioned that is designed to perform one or more functions when the continuum arm is in the correct position.The head of a continuum robotic arm is often equipped with an optical system so that the operator can view the head while it is inserted into its components and control it while it is performing its tasks. The optical system is also often coupled to a lighting system. Control cables to the fixtures, power connectors to the lighting system, and optical cables can usually run through the center of the joints in the continuum arm. This has the benefit of protecting the cables from any potential damage. All of these components and arm structures are permanently coupled to the actuators, which means that if the arm fails or has a problem, the entire continuum robotic arm needs to be replaced.

[0026] Figure 2 shows the external dimensions of the continuum arm robot system according to this disclosure. The continuum arm robots may be of the same size. Alternatively, the continuum arm robots may have different lengths and / or thicknesses. The continuum arm robot system features a first continuum arm robot 201 and a second continuum arm robot 202. Although described as a continuum arm robot, one of the arms may be a compliant, partially robotic arm robot. These continuum arm robots are controlled by their respective actuator packs. The first continuum arm robot is attached to the actuator pack to perform a desired task that will be performed by the robot system. The second continuum arm robot has a connection mechanism 203 at a point along the continuum arm robot section, which in Figure 2 is shown at the end of the arm. This connection mechanism is configured to grasp the first continuum robotic arm at a suitable location to support the first continuum robotic arm while it performs its desired task. The second continuum robotic arm is thus movable to a position suitable for supporting the first continuum robotic arm, allowing the system to compensate for loads at various points along the multiple continuums. Therefore, the continuum robotic arm system does not suffer from the large deflection that is common in single continuum robotic systems. Furthermore, the use of two continuum robotic arms coupled to reinforce each other allows for improved static and dynamic behavior of the system. Since both continuum robotic arms are movable, the operator can move the gripping position of the first continuum robotic arm to any suitable position for performing its task. For example, this position could be near the end of the first continuous arm robot, or near several joint sections away from the end.The presence of a second robotic arm can further benefit the system because it allows additional instruments to be delivered into the area when these instruments cannot be delivered through the conduit by a single snake-arm robot. The materials to be delivered to the instruments can be delivered through the core of the joint section of the continuum-arm robot, allowing for the delivery of multiple materials, such as air or different gases, to desired areas in a single motion. Similarly, the use of multiple continuum-arm robots in the system can allow for the presence of additional sensors that would not be present with the use of a single-arm robot. The length of the robots can be any suitable length. In some embodiments, connecting two continuum-arm robots results in a 6DoF after the first 6DoF from the end, which leads to optimal performance enhancement.

[0027] The head of a continuum arm robot may be equipped with sensors such as ultrasonic, camera, and depth sensors. Alternatively, these robots may be equipped with mechanical tools such as grinding or crushing devices, electrical tools such as lasers, or cutting tools that use gas. By utilizing multiple continuum arm robots, it is possible to move some of the sensors on a second continuum arm robot that "holds" the object, while having a free end effector on a first continuum arm robot that is dedicated to the operation. This potentially allows for more movement or a reduction in the external diameter of both robots. Depending on how the robots are connected, the connecting robots may also be used to supply pressurized air / liquid, gas, or electricity to the tools at the ends of the continuum arms. The purpose of using linked continuum arm robots is to increase rigidity and / or load capacity thanks to the interconnection. Additional advantages of linking continuous arms include the ability to "drive / pull" a main continuous arm by others to enhance the range of motion / accuracy of that main continuous arm, and the possibility of delivering more instruments, which would be possible with a single robot passing through a single entry / exit passage.

[0028] Figure 3 shows a schematic diagram of the operation of connected continuum robot arms. In this figure, the first continuum robot 301 is inserted through the access passage 306. Once the first continuum robot arm is positioned, or simultaneously with the insertion, the second continuum robot arm 302 may be fed in through the second access passage 304 so that both continuum robot arms are in the same workspace 307. The second continuum robot arm is directed toward the first continuum robot arm, in which case the second continuum robot arm can be clamped to or connected to the first continuum robot arm by the connecting mechanism 303. By combining the first and second continuum robot arms, the actuator head of the first continuum robot arm can then use its actuator head's tools or grippers so that the actuator head can work on the target object 305. In addition to typical continuum robot tasks, collaborative use enhances individual machining and manipulation tasks. In addition, collaboration can be used for inspection tasks requiring force interaction with the environment (e.g., ultrasound). The linking of the first and second continuum arm robots means that while working on a target object, the first continuum arm robot is supported and therefore undergoes less deformation than it would if it were operating independently. When the first and second continuum arm robots are to be removed, the clamping between the robots is disengaged. This allows the first and second continuum robots to be removed along their respective entry passages. The external configuration indicates the use of two entry points, which may be, for example, borescope holes in a gas turbine engine or other complex system. However, the robotic arms can be used at any suitable entry point into the system. Furthermore, it is not required that the two robotic arms use different entry paths; they can be inserted into the system adjacent to each other.The use of linked continuum robotic arms means that the entry / exit to the work area may be less than 50 mm, and the only size requirement is that the entry / exit simply needs to be large enough for the continuum arm to pass through. This means that linked continuum robots can be used in areas that are inaccessible to larger industrial robots. Therefore, the system can be used in the fields of aerospace, nuclear power, oil and gas, and communications, all of which have issues related to access for robots and human engineers. As those skilled in the art will notice, this is a non-exclusive enumeration, and the technology can be extended to be used in any suitable place.

[0029] To move the second continuum arm robot toward the first continuum arm robot, a camera system may be used in the first and / or second continuum arm robots so that the operator can orient the head of the second continuum arm robot toward the first continuum arm robot. Alternatively, or in addition, positioning sensors that provide relative positional information back to the operator may be used in both continuum arm robots so that the operator can manipulate the robots relative to each other so that they can establish a suitable coupling. Suitable sensors may be cameras or depth sensors for movement, and may be used individually or in combination. Magnetic sensors may also be incorporated. In addition, or alternatively, optical fibers may be used for shape detection. This may be done so that the sensors in each of the first and second continuum arm robots can provide the operator with precise positional data regarding the location of those sensors. Relative position control may be used when the two robot arms are approaching each other. Two robotic arms can move independently of each other before being joined, but once linked, they can be controlled as a single system. Once connected, control of the robotic system is performed by synchronized / coordinated control. Independent motion is due to the fact that the robotic arms have their own actuators. This allows for precise positioning of the second continuous arm robot, which is required because the joint between the first and second continuous arm robots determines the system's rigidity. Furthermore, this can be used to control the degree of motion available to the head of the first continuous arm robot. Motion control is achieved by connecting the second continuous arm robot closer to the end of the first continuous arm robot, which limits the movement between the joint and the end.Therefore, if the operator connects the second robot close to the head of the first continuum arm robot, this reduces the number of degrees of freedom of motion available to the first continuum arm robot, and further reduces flexion in the system. This means that there is greater positional control over the head, thus enabling the movement of heavier objects, or its use in processes where the head generates a reaction force, such as during solvent spraying. Therefore, the system can work in a confined space where if the head touches the side of an object, this could cause damage to the object. Alternatively, this process can be used to restrict degrees of freedom so that the head can be controlled to move only in a single plane, similar to a painter holding their wrist to create a straight line. However, connecting the second robot to the first continuum arm away from the head increases flexibility, and furthermore, the number of available degrees of freedom. Therefore, this could result in a more controlled continuum-arm robotic system for working in areas requiring greater dexterity. As discussed, the arm may be fitted with a “holding hand” to increase support to the arm in order to perform tasks. This hand would enable a continuum-arm robot of the same size to perform heavier and stronger tasks than it could perform without the hand. Having such a system could provide support to the head while performing tasks in which force is applied to the head of the arm performing the task, such as spraying. In such cases, the presence of a secondary arm acts as reinforcement. The use of such a system could prevent damage to the surrounding area from the robot head while performing such tasks.

[0030] In the example shown in Figure 3, the connection originates at the head of the second continuum robotic arm, but the connection may originate at any suitable point along the length of the second and first continuum arms. The connection point may be determined before the device is inserted. Alternatively, the operator may determine the connection point while positioning the continuum robotic arm in the workspace. This allows the linked continuum robotic arms to have heads that perform separate functions, which results in increased rigidity for the linked arms. Connections at points along the arms may be achieved, for example, by having an electromagnetic clamp at a point along the continuum robotic arm. This would allow, for example, one head to perform repair tasks such as spraying while the second head can provide lighting and camera systems. Alternatively, the two heads may provide complementary functions such as cleaning and repair. The presence of two continuum arms in the system further increases the supply to the work area because fluids can be transported by pipes along the center or periphery of the arms. Similarly, it is possible to supply optical systems, such as lighting and camera systems, to the work area. Thus, connecting further away from the head via the arms allows for independent control of the two heads of the linked system, and therefore these heads maintain maximum functionality at the end of the continuum arm from the point where the two arms are linked. Having two heads capable of performing different tasks within the same system increases the functionality of the robotic system. This further means that multiple processes can be performed simultaneously, which reduces the repair time for complex tools and therefore reduces the downtime of those tools.

[0031] The robot arms can be connected by several different options. The connection system can be fabricated by means of magnetic or adhesive coupling of the continuous arms as a single unit. Alternatively, or in addition, the connection system can be achieved by mechanical, pneumatic, or hydraulic clamping systems. The control unit of the connection system is linked to a connection control unit on the actuator pack, and based on signals, the control computer program activates that unit to initiate the process of connecting a second continuous arm robot to the first. For example, in the case of hydraulic and pneumatic connection systems, the connection control unit will control the fluid supply to the clamp to close the clamp around the arm of the first continuous arm robot. In an alternative example of using electromagnetic coupling, the connection control unit supplies the necessary current to the electromagnetic clamp to engage the electromagnetic clamp.

[0032] The control system is required to control at least a two-arm continuum robotic system, as shown in Figures 4a and 4b. The system shown in Figure 4a represents a system in which a first compliant robot 401 and a second compliant robot 402 each have their own local control systems 403 and 404. These control systems are used to provide signals to actuator packs 405 and 406 used to control the movement of the individual continuum robots. The overall control system links the two local controllers to provide overall control when the robots are coupled together. Figure 4b shows an alternative method in which the first compliant robot 401 and the second compliant robot 402 each have their own local control systems 403 and 404 for providing signals to the actuator packs of individual actuators 405 and 406. Local controllers are controlled (disabled) or ignored when the robot is controlled by an external total control system 407, which is coupled to the local control units so that the system operates as a whole and provides the required signals to those local control units. The local and / or total control systems may run on a computer having a processor and memory suitable for running a suitable control program. The computer may further have means for user input, which may be a USB port connected to a joystick moved by the operator to control the robot's movement. Additional functionality of the computer is desirable, which may include a second user input device such as a keyboard, or through commands entered via a touchscreen device. Further functionality such as a mouse may also be used. The computer may further require means for connecting to actuator packs associated with different continuum arm robots, which may be done by physical linking using cables or wirelessly. Further features of the systems, depending on the system configuration of those systems, will be apparent to those skilled in the art.The computer hosting the overall control system may also be the same system having local control units. In such cases, the local control units may be part of the overall control program, but may simply deal with a single actuator and control the robot to which those local control units themselves are associated. Alternatively, the overall control system may reside on separate computers / multiple computers for the local control systems to the robot. In such cases, the computer hosting the overall control system may be linked to the computers / multiple computers using any suitable means, and signals may be read and transmitted by the overall control system. The local systems may then provide and transmit signals to the actuator pack to which those signals are associated.

[0033] A system with multiple linked continuum robotic arms has three different operating modes. The first is a system in which all arms remain active after coupling. Such a system allows a second or further robot in the system to have a controllable head, or to move the position of the first robot body so that the head can be manipulated to a new position. A second way of controlling a linked robotic system is to have one or more active robots and the remaining robots with passive control. This allows for limited control of the second or further robots in the system, for example, allowing for minute movements of the robot system so that those robots can approach a larger area of ​​the workspace. A third option is to have one active robot and other robots that are rigid / idle once coupled. This means that the second and further robots are used purely in a supporting role to the first robot. The selection of the operating mode needs to be modeled as part of the kinematic modeling of the robotic system, which is programmed into the computer. Having multiple moving robots increases the complexity of the model and the system requirements necessary for the system to operate.

[0034] To achieve the desired system, it is important to have a control system capable of controlling the movement of multiple linked continuum robotic arms within the system. Each continuum robotic arm has its own controller, which is linked to an actuator pack. These local controllers are then linked by a total control system that can control the robots when they are coupled together. Therefore, the control system may further be configured to control the controllers linked to the first and second continuum robots when those controllers are not linked, but the primary objective is the control of the system when linked. The total control system is responsible for the motion control, synchronization, and overall planning of the linked robotic system. Therefore, the local controllers for the first, second, and potentially further compliant robots must both have a synchronized clock, the signal of which is fed back into the robot's total control system. The overall control system, along with local controllers, is also responsible for obtaining feedback from sensors installed within the robot, but the overall controller takes in signals from all robots, while the local controllers simply do so for the robots associated with those local controllers. The overall controller processes the above signals and may provide feedback of the sensor readouts to the operator via a visual display unit linked to the controller. The system may also be configured to provide an alarm if a sensor records any dangerous or erroneous signal. The alarm may be audible or visual to alert the operator. Sensor information is also used to calculate the motion of the linked continuum robot system. Part of this information may be fed into a kinematic model representing the functions of the system and robots so that accurate system mapping, as well as accurate planning of paths and / or tasks, can be carried out.Kinematic modeling will need to accommodate the representative rigidity of all joints in the robot, and furthermore, be able to compensate for any increases in the rigidity of associated joints. In addition to modeling, a feedback system may be used to continuously improve the modeling and to increase the accuracy of the model. This feedback system will take in information from sensors and visually to increase the performance and usability of the system. Any determined movement is then sent as a command into the local control units of the first or second robot so that this command can be converted into robot motion by the actuators of those robots. Furthermore, this data may allow the overall control unit to determine whether any further corrections or compensations need to be automatically input into the robot to ensure correct positioning. Thus, at least in controlling some movement of the linked system, the overall controller is responsible for and in relation to the signals sent to the local control units associated with the actuator pack, or directly to the actuator pack. The overall controller may also receive feedback from actuators and / or local controllers to the first and second compliant robots. This allows the controller, and possibly the kinematic modeling, to be updated with information about the individual controls of the compliant robots in the system. Although the local controls are described as separate from the overall controller, they may be located on the same computer system, which can individually address the robot actuator packs. In this example, each local controller is an actuator, and has the functionality required to address the actuators that control each of its respective robots, as well as to provide feedback and be controlled by the overall controller. Alternatively, separate computer systems may be used for each of the controllers.The discussion is based on robots clamped together as a single unit, but the system can also be used to control the movements of two robots working on linked tasks within a workspace. This system can be used, for example, for inspection systems and work implements, or for cutting implements and the use of ignition sources for cutting implements.

[0035] For the step of connecting the robots as a whole, it is necessary that there be means of joining the robots without damaging each other, such as contact and grasping / otherwise. To enable this means, the control unit may have a relative motion control unit, which allows one or both robots to have controlled motion when they are in a desired position close to each other after the second step described above. The controlled motion may, on the one hand, be performed by an operator using visual or sensor signals to determine the position of the robots relative to each other. Alternatively, this controlled motion may be performed by a pre-programmed movement of the robots by a control system that uses information from sensors to guide the robots as a whole. To enable this controlled motion, the robots may have one or more position sensors, which allow the position of the robots and / or the position of the robots relative to other robots in the system to be determined, and this position may be sent to a total controller so that the total controller can use these signals to monitor and control the robots' motion. The system may also be equipped with a camera on the coupling mechanism so that the coupling process can be verified by the operator, and the operator may disable the process manually if the operator confirms that a failure has occurred in an automated coupling case. This camera may be part of a vision odometry system. The overall control unit may use predictive coupling based on the kinematics models of different robots in the workspace, and the expected characteristics, as well as the movements and motions of those robots, are modeled together to determine the contact points. This modeling may also be further improved by having an open loop, where sensors capable of measuring position and / or shape are used to compensate the model, so as to result in a more accurate reconstruction of the actual behavior of the robots.If the clamping mechanism is a magnetic clamp, this means that less control is required when the robot is positioned close to something and can be active in order to bring it to a clamping connection. Not only is the movement approaching the connection important, but the clamping process itself, which can also be controlled by a holistic control system.

[0036] Once the robots are moved to their proper positions, the clamping process may begin. This process may be automatic, based on modeling and automated programming within the overall controller. Alternatively, the process may be operator-initiated, based on operator signals, once the operator is confident that the robots are correctly positioned for clamping. If the robots are not correctly positioned, the operator may take over manual control of the robots through the overall controller or local control units to correct the final part of the positioning for coupling. With the robots in the correct position, they can then be clamped. As discussed above, depending on the number of robots in the system, the clamping of the first and second robots may occur first, followed by a second clamping process with the third robot and the second and / or first robots. The order may also depend on the size of the robots involved. In this example, the operator and / or the overall control program may have to compensate for any deflection of the robots after the first coupling step prior to the second clamping step, otherwise the system may already be in position. The robots are thus activated to clamp each other, either automatically or manually. In the case of electromagnetic clamps, this is no more complex than having a wrap-around clamp, where activation, either manually or automatically, initiates the clamping step of engaging the clamping means to grasp another robot in the system. Once the connection is made, the connection can be checked to verify that it is properly clamped. This can be done by using one or more sensors, such as pressure sensors, on the clamp and / or on the clamping area. In addition, or alternatively, the system may have a closed-circuit loop for determining whether a connection exists between the robots. In addition, or alternatively, there may be a camera system positioned near the clamps so that visual feedback can be provided to the operator for other means described.When a robot in a system is clamped, a force may be applied to one or more of the robots to ensure that the clamping is secure. This could be a small movement, or it could be a predetermined force or torque applied to the clamped robot. The predetermined force may be equal to or greater than the expected force that will be applied to the clamping area during task execution. If there are three or more robots in the system, the force may be applied by the expected degree of force at each point, and the movement / force may be applied individually or as a whole. This can form part of a check sequence that the overall controller goes through to ensure that the system is secure. For example, the system may determine readings from sensors in the clamping area to check if those readings are within a predetermined range. The system may then determine a voltage through the system to check the closed-loop system. If both of these are acceptable, the system may then, as a final check, apply a force at the clamping point. If one or more of the sensor, voltage, and / or applied force values ​​are not within a predetermined range, the system may be automatically programmed to disengage the clamp so that the previous two steps can be performed again to obtain a more secure clamp. If those values ​​are within a predetermined range, the task can be performed by the device on the robot. The overall control system may monitor the closed-loop voltage and / or sensor values ​​during task execution, which can act as an interlocking device in the system, and if the values ​​are outside the correct range, the system may be shut down to prevent damage to the workplace and / or the robot. Once the robots are connected, one of the robots may be powered off to its idle state.

[0037] Similar to the engagement sequence, the disengagement sequence requires inspection to ensure that the robots and the workspaces in which they operate are not damaged. The initial step in this process is to inspect whether it is safe to release the robots and / or the workspaces relative to them. If it is not safe, further movement of the robots is required to position them in a safe location so that they can be disengaged. The order of disengagement may vary depending on the number of robots in the system, which may depend on the size, function, and / or capabilities of the robots in the system. A robot may be activated if it was idle because it was being used as part of a supporting role. The clamping mechanism can be disengaged by activating all robots in the system into their capable state. This may be done either by the operator commanding the overall control system to release the clamps, or automatically by the overall control program. Once the robots are released, the system may undergo a series of checks to determine that the disengagement process was successful. This may involve reading voltages from a closed-loop system, and / or acquiring / receiving signals from sensors around the clamp and / or positional sensors used for positioning the robots prior to coupling. At this point, the robots are under the control of their local controllers and can therefore be operated individually to make robot extraction less complicated. Once it is determined that the robots are no longer clamped and can be safely disengaged, they can then be removed from the workspace. As the robots are outside the workspace, they can be powered off and stored.

[0038] When the robots are positioned close to each other at their desired locations, or at the latest when they are engaged, the total control system takes over the operation of the system. Immediately after the robots are engaged, motion and control are administered by the total controller. In cases of three or more robots in the system, then two clamped robots may be controlled as a single entity by the total controller, while a third robot, or more, may still be under local control, resulting in a hybrid system operation. When the system is clamped, the total control unit has pre-programmed settings for the nature of the system, whether the robots will be passive, idle, or active. With this information, the total controller can switch off power to a passive robot, since that robot does not require any additional power during its use. Alternatively, the total controller may simply power the robot's functional necessities, such as sensors and clamping circuits. At this point, the overall controller will also become responsible for data collection from sensors and / or cameras on the robots, depending on the functionality of those robots. Types of robots that may be used for such linked robotic systems include blind robots without sensors—these robots may only have functional instruments at their ends; observation robots with sensors and / or cameras—for example, only a borescope; and hybrid robots with both instruments and sensors. An example of such a system may be an active robot used to drive a passive robot, having two or more active robots in the system, or having a blind robot guided by a passive robot.

[0039] A key characteristic of a total control system is that it requires the ability to control multiple robots as a single unit. This is achieved by utilizing local control units for the robots within the system and linking the outputs to these local control units to the total system's movement, or by replacing the local control units and providing direct signals from the total control unit to the actuator packs that govern the robots' movements. As part of this, the total control unit must receive synchronous clock signals from the robots and their controllers, enabling the system to link feedback signals from actuators and / or sensors from the robots, and to determine their impact on multiple robots within the system. This allows for accurate feedback-based modeling of robot motion and position, and the ability to send synchronous signals to actuators to move the robots in a coordinated manner. The system's movement needs to be coordinated to ensure that the robots operate safely and securely when linked. Another issue that requires the overall controller to take responsibility for is managing redundancy between robots. This means that the overall control system needs to be able to pause motion within a given degree of freedom in one or more of the robots when they are connected. The reason for this is that clamping results in a locking point, which inherently reduces the available degrees of freedom for the system. If the overall controller is not responsible for this, there is a potential for damage to one or more of the robots. For example, if a second robot grasps the first robot with its head, the system loses six degrees of freedom, and therefore six of the motors in the actuators are providing conflicting signals to another six motors used to drive one or the other robot.The number of degrees of freedom lost is not fixed but depends on the nature of the clamping, and therefore, if a robot connects to two other robots, in one connection, the system may lose a different number of degrees of freedom relative to the other points of contact. This, therefore, requires responsibility, and the total controller must manage this so that it does not input conflicting information into the actuator pack. Therefore, the system needs to process the motion commands of the robot system so that it achieves motion without providing conflicting advice to different motor banks in the actuators, and can send any further motion into the coordinated set of motors in one or more of the actuators. The total controller has several options to overcome this, firstly, it can deactivate a given motor in the actuator for each of the robots so that no conflicting signals are sent, which may be partly due to cutting off the power to the motor or not providing any signal at all. The overall controller can be programmed to deactivate an appropriate number of motors from each actuator, so that this number is entirely from one actuator, or a specific number from each actuator bank—for example, in a system that loses six degrees of freedom, it could be 3 and 3, or 4 and 2, or 5 and 1. Secondly, signals to the actuator banks can be provided in such a way that the actuator movements are coordinated to avoid conflicts. This can be achieved by compensating for any conflicting signals by modeling the system's motion so that conflicts are determined and compensated for in the inputs to the actuators. The overall control unit can switch between two modes, for example, under automatic motion, the system is compensating, but under manual control by an operator, the system deactivates a bank of motors in the actuators.This is further relevant when the total controller provides signals to each actuator pack in a synchronized manner, and therefore synchronization between controllers is crucial so that the motor motions are linked and synchronized. If the system operates outside the kinematics model discussed above, the total controller must also be responsible for the size, weight, and flexibility of the robots in the system to bring about an accurate model. This can then be fed into the signals provided to the actuators to control the robot's motion. The total controller may be programmable so that the system can provide compensatory forces to one of the robots while it is performing a task, which could be to increase the robot's rigidity or increase the accuracy of the robot's head positioning while it is performing the task. The total controller is responsible for the system performing the desired task. Therefore, the overall controller is responsible for sending signals to the robot actuators to supply the instrument, and / or any tools and / or supplies that the instrument requires to perform its task.

[0040] The program controlling the global controller and / or local controllers may be linked to an imaging device in one or more continuum-arm robots, for example, the device may involve one or more arms having fiber optic cameras, the camera's output being fed into a decoder, the decoder's signal being fed into a computer and into the program so that the operator may have a raw (immediate) view of the continuum-arm robot's movements in situ, thereby allowing the operator to guide the robot to the desired position. The computer program also has inputs to enable the connection system to be operated when desired. The output from the computer program is then sent to an actuator pack to control the output of the continuum robot. The associated actuator pack, continuum-arm robot, features inputs that can be linked to a computer, which may be the presence of a cable jack for inserting a networking cable, or the presence of a wireless transmitter card, or both. These are coupled to a processor in the actuator pack. The processor is coupled to an encoder used to control the movement of the actuators. The actuators in the actuator bank of an actuator pack can be paired. The actuators must have the ability to produce precise, controlled motion and sufficient torque to move tendons to move joints in a continuum arm. The actuators can be brushless servo motors. Such servo motors offer the advantages of being lightweight, while still producing torque and the precision of motion control required for the accurate positioning of a continuum arm robot. Alternatively, these actuators can be any other suitable actuators, which will be apparent to those skilled in the art. The actuators can be mounted on a frame, which allows them to be connected to a bank, and the bank can be linked to form an actuator pack when combined with other paired actuators on the frame.The actuator's drive electronics are coupled to the actuators to control their movement. The actuator pair may also be equipped with load cells, which can measure the load on the actuators and provide signals of the relative load to control and return to the servo drive used for each actuator. Thus, precise control of the actuators can be achieved. The movement of each actuator sets the tension in the tendons within the arm. Controlling the tension results in the movement of each joint in the arm, which causes deflection of the arm's position from being linear. This makes it possible to manipulate the robot and head to the appropriate position. The second continuous arm robot and its actuators differ from those of the first continuous arm actuators because the second continuous arm robot also features a coupling controller mechanism that allows the second continuous arm robot to be connected to the first continuous arm robot. While the example described was for a continuum robotic arm operated by cables, it is also possible to use non-cable drive systems such as pneumatics or hydraulics with continuum robotic arms controlled by electric motors.

[0041] The operation of the robotic system is illustrated by the flowchart in Figure 5. The first step is to insert the first, second, and any further compliant robots into the workspace. This can be done one at a time or simultaneously, depending on the nature of the workspace into which the robots will be inserted and the possibility of entering and exiting the workspace from different entrances and exits. The entrance and exit areas may be entrances and exits such as borescopes in a gas turbine engine, or other restricted space entrances and exits. The second step is to control the relative position of each robot in the system so that they are positioned at the desired location of the robots near the relative task they are set to perform. For example, if there is only a two-robot system with a first robot having a working head and a second robot having a gripping head, the second robot simply functions to support the first robot. The first robot is positioned so that its head is close to the task that needs to be performed, while the head of the second robot is moved to a position close to the gripping point of the first robot. In the case of a non-gripping system, the first robot is moved to the desired area to perform the work, and the second robot is moved to be positioned close to the first robot. As those skilled in the art will notice, depending on the number of robots in the system, and the functionality and gripping of those robots, there are several ways in which different robots can be positioned relative to each other, which further relates to different robot gripping options. If desired, the robots can now be connected by positioning them close to their desired positions. Depending on the number of robots in the system and the number of robot clamping systems, the sequence of connections can vary. The simplest is the two-robot system described above, in which the second robot clamps the first robot.The final stage of connection can be controlled by addressing individual robot controllers or by utilizing a holistic robot controller. For simple systems and minimal connections, using local robot controllers may be simpler, but if a robot is required to clamp with two or more robots, a holistic control system may be more appropriate because it can control the entire system. With the robots connected, the third step is to produce controlled motion of the robots, which is managed by the holistic controller and enables any desired number of robots in the system to perform their desired tasks. This may necessarily involve two or more robots being used for the same task or producing simultaneous work on the same area of ​​the workspace. Alternatively, one head may be used for visual inspection while another head performs the task. Once the task is performed, the holistic controller can then be used to bring about coordinated separation of the robots, so that each individual robot returns to the control of its local controller. Ultimately, the separation sequence will depend on the number of robots in the system. In a system with three or more robots, the separation sequence may further involve the disengagement of one of the robots so that it can be removed from the system and replaced by another robot with a different function. For example, a three-robot system may initially include a clamping robot, a borescope, and a grinding robot. The system will clamp all the robots into position before the grinding operation, and once the grinding operation is complete, the clamping robot will release the grinding robot so that it can be removed. The coating robot may then be inserted into the workspace and positioned relative to the clamping robot and the desired area to which the coating will be applied. The clamping robot may then grip the coating robot so that it can perform its desired task.Upon completion of this task, the robots may then undergo a separation sequence. Once all robots are disconnected, they may then be moved out of the workspace and back to their original positions.

[0042] Figure 6 shows an example of a three-continuum robot system. In this figure, the first continuum arm robot 601 extends from its actuator pack, located outside the workspace, to an end-effector 604 required to perform essential tasks of the robot system. The second continuum arm robot 602 extends from a different entrance, and again, its actuator pack is located outside the workspace. The continuum arm robot extends into the workspace, and at its end-effector, the second continuum arm robot has a shaped two-piece clamp 605 used to engage around the body of the first continuum robot and clamp the first continuum robot in place. A third continuum arm robot 603 is also present in this example. The presence of the third continuum robot provides additional support to the first continuum arm robot, enabling it to support loads greater than those the first continuum arm robot could support on its own or together with the second continuum arm robot alone. Like the first and second continuum arm robots, the actuator pack of the third continuum arm robot is positioned outside the workspace. The third continuum arm robot is shown to extend and extend toward the first continuum arm robot, and in that case, the third continuum arm robot clamps / gripping toward the first continuum arm robot using an electromagnetic clamping mechanism 606 that engages with the magnetic section 607 of the first continuum arm robot. The tip of the first continuum arm robot is thus free to perform essential work tasks within the workspace. An alternative to the three-robot system would be that the first and third continuous arm robots have functional heads that can be used for a certain purpose, while the second continuous arm robot features two clamps so that it can engage with the first and third continuous arm robots. Thus, the second continuous arm robot acts as a reinforcement for the first and third continuous arm robots.

[0043] Figure 7 shows an example of a clamping mechanism between a second continuum robotic arm and a first continuum robotic arm, as shown in Figure 6. The clamping mechanism 703 is positioned at the end of the second continuum robotic arm 702. As the second continuum robotic arm is moved closer to the first continuum robotic arm 701, the operator ensures that the connection system is in an open position, which ensures that the connection system can be positioned relative to the first continuum robotic arm without damaging it. This further means that the connection system is already in a position to connect to the first continuum robotic arm. Once the connection system is positioned around the first continuum robotic arm, the operator can initiate a signal to close the connection system so that the first continuum robotic arm is held by the second continuum robotic arm. Sensors such as pressure sensors may be attached to the connection system to inform the operator that there is contact at one or more points of the connection system and that the connection system can be safely closed. To release, the operator issues a command to open the connection system, causing the second continuum arm robot to release the first continuum arm robot. The behavior of the connection system can be rigid. In this case, it is possible to achieve a connection with high rigidity. Alternatively, the connection system can be compliant such that it exhibits elastic behavior, having lower rigidity but higher flexibility. Furthermore, the connection can be constrained to fewer than 6 degrees of freedom, which allows for one or more relative modes of motion between the robots. In this case, the connection would be equivalent to rotation, free-moving, spherical, linear, or other joints, instead of behaving as a fixed object. As discussed above, one of the continuum arm robots may be a compliant, partially robotic arm rather than a compliant robot.In this example, the single continuous arm robot will still be associated with its own actuator pack and will operate in the same manner as if it were a continuous arm system, except that it will have less control over the positioning and motion of the single continuous arm robot itself.

[0044] Figure 8 shows an example of a control system in which a third robot is supplied into the workspace. In this figure, a first compliant arm robot 801 is provided with an associated actuator pack 802, which has electronic and electromechanical devices for controlling the compliant robot and activating the instrument. This actuator pack is coupled to a local controller 803, which is used to move and operate the robot when it is operating individually. A second compliant robot 804 is provided with an associated actuator pack 805, which is coupled to its own local controller 806. The second compliant robot clamps to the first compliant robot using a clamp 807. These two robots are linked by a global controller 808. A third compliant robot 809 is provided into the system. This compliant robot has its own actuator pack 810 and a local controller. In this example, the third compliant robot is not coupled to the control of the overall controller of the first and second compliant robots, but the local controller of the third compliant robot is linked to the overall controller and provides sensor and positional data to the overall controller. This allows the computer program running the overall controller to know details about the third robot and the signals it receives from sensors. This can be used as part of a feedback system so that the overall controller has as much information as possible about the system. In such an example, the third compliant robot may not simply be a flexible robot with, for example, a borescope.Therefore, the movement of the third compliant robot is not controlled by the actuator pack and its local control unit, which is simply used to acquire the video signal from the borescope camera. The first compliant arm may be provided with a clamp for engaging with this third compliant robot.

[0045] In the example described above, the system is shown to have two linked continuum arms, but it is possible for the system to have three or more continuum arms linked together. Increasing the number of arms in the system allows the system to have a greater degree of functionality.

[0046] It will be understood that the present invention is not limited to the embodiments described above, and that various modifications and improvements can be made without departing from the concepts described herein. Any of the features can be used separately or in combination with any other features, except where mutually exclusive, and this disclosure extends to and includes all combinations and subcombinations of one or more features described herein. [Explanation of symbols]

[0047] 101 Continuum Arm Robot Section, Continuum Arm 102 Actuator Pack 103 Actuator 104 Rail or support 105 Power and signal cables 106 joints 107 joints 108 joints 201 First continuous arm robot 202 Second Continuum Arm Robot 203 Connection mechanism 301 The first continuous robot 302 Second continuous arm robot 303 Connection mechanism 304 Second entrance / exit passage 305 Target object 306 Entrance / Exit Passage 307 Workspace 401 The first compliant robot 402 Second compliant robot 403 Local Control System 404 Local Control Systems 405 Actuator Pack, Actuator 406 Actuator Pack, Actuator 407 External Total Control System 601 First continuous arm robot 602 Second continuous arm robot 603 Third Continuum Arm Robot 604 Tip 605 2-piece clamp 606 Electromagnetic clamping mechanism 607 Magnetic section of the first continuum arm robot 701 First continuous arm robot 702 Second continuous arm robot 703 Clamping mechanism 801 First compliant arm robot 802 Actuator Pack 803 Local Controller 804 Second compliant robot 805 Actuator Pack 806 Local Controller 807 Clamp 808 Total Controller 809 The third compliant robot 810 Actuator Pack

Claims

1. 1. A control system for a compliant robotic system including at least two compliant robots, each compliant robot having its own actuator pack, the control system comprising: an individual local control system associated with each of the actuator packs, the individual local control system providing control signals to the actuator packs to cause movement among the at least two compliant robots; a global control system for controlling the global motion of the robots when the robots are in proximity in a workspace, the global control system providing signals collectively defining a global control to the actuator packs associated with the at least two compliant robots to cause linked movements of the compliant robots, and receiving synchronized clock signals from the compliant robots; each individual local control system is provided with a clock, the clock of each individual local control system being synchronized with other clocks; and the global control system is provided with a redundant control system that constrains the motion of the compliant robot within predetermined degrees of freedom such that the motions of the at least two compliant robots do not conflict when operating under the global control system; the at least two compliant robots include a first compliant robot and a second compliant robot, the second compliant robot comprising a connection mechanism configured to grasp the first compliant robot at a plurality of positions along the first compliant robot.

2. 2. The control system of claim 1, wherein at least one of the compliant robots is provided with a clamping system for linking the at least one to at least other compliant robots in the system, and wherein a mechanism of the clamping system is controlled by either the local control system associated with the arm provided with the clamping system or the global control system.

3. The control system of claim 1 , wherein the compliant robot is provided with sensors that provide signals to both the local control system and to the global control system.

4. 2. The control system of claim 1, wherein the local control system is programmed with a kinematic model of the respective robot in motion that is used to compensate the signals to the actuator packs when movement commands are input.

5. 2. The control system of claim 1, wherein the overall control system is provided with kinematic models for all of the robots in the system and models for connected systems that are used to compensate the signals provided to the actuator packs when movement commands are input.

6. 2. The control system of claim 1, wherein each local control system and the overall control system are provided on separate computer systems, and the local control systems are linked to the overall control system.

7. The control system of claim 1 , wherein the redundant control system disengages as many motion control actuators as required from one of the actuator packs.

8. 2. The control system of claim 1, wherein the redundant control system disengages a required number of motion control actuators from each of the actuator packs.

9. 10. The control system of claim 1, wherein once the robots are in position, the overall control system places one or more of the compliant robots in an idle state while at least one of the compliant robots remains active so that a human operator can still control the movement.

10. 10. A method of controlling a plurality of compliant robots according to any one of claims 1 to 9, comprising the steps of: inserting a plurality of compliant robots into a workspace; manipulating the movement of the compliant robot using individual local control systems to move the compliant robot to a first desired position; operating the compliant robot in the determined position, the local control system being paused and the global control system taking over motion control of the compliant robot as part of a system; performing a determined task using the compliant robotic system; positioning the robot at a second desired position; disengaging the global control system and reengaging the local control system; removing the compliant robot from the workspace; A method comprising:

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