Mobiles Robots

Abstract

A mobile robot comprises a main body portion having a plurality of drive units configured to generate driving forces by driving rotary vanes, and a plurality of support portions provided on the main body portion and configured to come into contact with a predetermined contact surface to support at least a part of the main body portion. When motion control is performed while the main body portion is supported by the plurality of support portions, in an assist control for the motion control, part or all of the plurality of drive units are driven to generate an assist support force outside an actual support range when a target pressing position related to the transition of a center of gravity of the main body portion in the motion control is not within the actual support range.in which the main body portion is actually supported by predetermined support portions in contact with the predetermined contact surface among the plurality of support portions.,

Description

[TECHNICAL FIELD]

[0001] This invention relates to a mobile robot that can fly and move. [State of the art]

[0002] In recent years, unmanned aerial vehicles have been used for various purposes, and their development has been actively promoted. Remote-controlled unmanned helicopters, or so-called drones, are used as unmanned aerial vehicles. Examples of the use of drones for agricultural purposes include spraying agricultural chemicals, monitoring crop growth using onboard cameras, and generating air currents to protect crops from frost damage (see, for example, Patent Literature 1). In addition, robots that can fly with arms or similar devices to perform a predetermined task have been developed and are installed on unmanned aerial vehicles, allowing the robots to be used not only for agricultural purposes but also for other purposes (see, for example, Patent Literature 2).

[0003] Furthermore, Patent Literature 3 discloses a mobile robot that performs a flying motion by drive units and a walking motion while standing on the ground. In the mobile robot, walking is performed by two leg portions, and when a tilt or skew of a main body portion of the robot is increased by a sensor during its walking motion, the posture of the robot is controlled using the drive units so that the tilt is within a predetermined angle range. [Citation list][Patent literature] Patent Literature 1: Japanese Patent Application Laid-Open No. 2018-000015 Patent literature 2: WO 2016 / 193666 Patent Literature 3: Japanese Patent No. 6733965 [Summary of the invention][Technical problem]

[0004] In a case where the main body portion of the robot is moved in a state where the robot is in contact with a contact surface such as the ground, that is, in a case where the robot's movement is performed by contact with the contact surface, such as walking, rather than its movement by flying (in the present application, the former form of movement is referred to as "flying movement" and the latter form of movement is referred to as "contact movement"), the main body portion of the robot must perform its movement while being supported by support portions (e.g., leg portions) in contact with the contact surface in order to prevent the main body portion from tipping over. Generally, in the contact movement at a high movement speed, it becomes difficult to maintain the stability of the robot main body, thereby increasing the possibility of tipping over.In addition, the main body section of the robot swings during movement, which hinders the acquisition of information about the position and posture of the robot required for stable contact movement of the robot, thus the possibility of tipping over of the robot main body section cannot be ruled out.

[0005] The present invention has been developed in consideration of the above-mentioned problems, and an object of the present invention is to provide a robot technology in which a stable contact motion is realized in a robot moving in contact with a contact surface by preventing tipping of the main body portion of the robot as much as possible. [Solution to the problem]

[0006] In order to solve the above-mentioned problems, the present invention adopts a configuration in which a robot according to the present invention is provided with support portions that come into contact with a contact surface, and the driving forces are controlled by drive units. Furthermore, the robot is provided with a first control unit for the contact movement when the contact movement is performed using the support portions, and a second control unit configured to perform assist control for supporting the contact movement using the drive units. With such a configuration, it is possible to realize stable contact movement of the robot.

[0007] Specifically, a mobile robot according to the present invention comprises: a main body portion having a plurality of drive units configured to generate driving forces by driving rotary vanes; a plurality of support portions provided on the main body portion and configured to come into contact with a predetermined contact surface to support at least a part of the main body portion; a first control unit configured to perform motion control in which the main body portion moves on the predetermined contact surface by the plurality of support portions while being supported by the plurality of support portions;and a second control unit configured to perform assist control for the motion control by the first control unit using part or all of the plurality of drive units. Then, in the assist control, when a target pressing position related to the transition of a center of gravity of the main body portion in the motion control is not within the actual support range in which the main body portion is actually supported by predetermined support portions in contact with the predetermined contact surface among the plurality of support portions, the second control unit drives part or all of the plurality of drive units to generate an assisting support force outside the actual support range, which assists a shortage of a support force required for the motion control. [Advantageous effects of the invention]

[0008] In the mobile robot moving in contact with the contact surface, it is possible to avoid tipping of the main body section as much as possible, thereby realizing stable contact movement. [Brief description of the drawings] Fig. 1 is a view illustrating a schematic configuration of a mobile robot according to an embodiment. Fig. 2 is a functional block diagram showing an image of functional units formed in the mobile robot according to the embodiment. Fig. 3 is a first view for explaining the assistance control for supporting the walking of the mobile robot. Fig. 4 is a second view for explaining the assistance control for supporting the walking of the mobile robot. Fig. 5 is a third view for explaining the assistance control for supporting the walking of the mobile robot. Fig. 6 is a fourth view for explaining the assistance control for supporting the walking of the mobile robot. Fig. Figure 7 is a fifth diagram for explaining the assistance control for supporting the walking of the mobile robot. Fig. 8 are diagrams illustrating the transitions of a posture change of the mobile robot according to the presence and absence of an assistant controller in the mobile robot. Fig. 9 are sixth views illustrating the assistance control for walking of the mobile robot. Fig. 10 is a view illustrating a first form in which assistance control for walking of the mobile robot is performed. Fig. 11 is a view illustrating a second form in which assistance control for walking of the mobile robot is performed. [Description of the embodiments]

[0009] A mobile robot of the present embodiment can generate a driving force for raising or lowering a main body portion thereof by means of a plurality of driving units provided on a main body portion side. Each of the driving units has a rotary vane, and a driving force generated by each driving unit is determined by rotationally driving the corresponding rotary vane. Preferably, the driving forces of the respective driving units can be controlled independently of each other. The arrangement of the plurality of driving units on the main body portion can be arbitrarily designed. The mobile robot can be configured to fly (ascend, descend, rotate, etc.) by balancing the driving forces of the respective driving units provided on the main body portion.

[0010] The plurality of drive units provided on the main body portion may all be of the same type or a mixture of different types.

[0011] Then, the mobile robot is equipped with a plurality of support sections so that its main body section is supported against a predetermined contact surface. Note that the support of the main body section by the support sections can be in the vertical direction or in a direction other than the vertical direction. In the former case, the support sections may be formed as leg sections that come into contact with the contact surface so that the main body section can walk on it. In the latter case, the support sections may be formed as arm sections that serve to move the main body section into contact with the contact surface while grasping. Configurations of the support sections other than those described above can also be used.

[0012] Here, in the mobile robot, the first control unit controls the execution of a contact movement in which the mobile robot moves on the contact surface using the plurality of support portions. The first control unit controls the drive of the plurality of support portions to prevent the main body portion from coming into contact with the contact surface due to tipping over, that is, to execute a contact movement while maintaining support by the support portions. Here, when the control is performed by the first control unit, the contact between a part of the plurality of support portions and the contact surface may be temporarily or temporarily released, so that the stability of the support of the main body portion by the plurality of support portions may be reduced.Such a reduction in stability does not necessarily cause the mobile robot to tip over, but it is desirable that the degree of reduction be as small as possible. Particularly when it is difficult to predict the condition of the contact surface with which the support sections come into contact, the possibility of tipping increases due to the inability of the first control unit to provide good control of the movement.

[0013] Therefore, when the possibility of such tipping increases, assistance control for motion control is performed by a second control unit. In the assistance control, when a target pressing position is not within an actual support range, a supporting force by the support portions required for stable contact movement is considered insufficient, thereby increasing the possibility of tipping. The target pressing position is a position of a zero moment point (ZMP) of the mobile robot assumed when the first control unit performs the contact movement. The actual support range is a range on the contact surface defined by the contact parts of those support portions in contact with the contact surface among the plurality of support portions.As described above, when the possibility of tipping over is estimated to be high due to a correlation between the target printing position and the actual support range, the driving forces generated by driving part or all of the plurality of drive units are used to generate an assisting support force outside the actual support range, thereby compensating for a lack of support force.

[0014] In this way, when it is determined that the possibility of tipping is high, the driving forces of the drive units are used to assist the lack of supporting force by the plurality of support sections, and thus it is possible to accurately provide the assisting support force for preventing the mobile robot from tipping over, regardless of the movement or the posture and position of the support sections. This simplifies the configuration for preventing the mobile robot from tipping over, so that, for example, the arrangement of sensors or the like for smooth contact movement can be eliminated. Even if the condition of the contact surface is not as expected, the assisting support force can be accurately generated by appropriately driving the drive units, whereby stable contact movement can be realized.

[0015] Specific embodiments of the present invention will be described below with reference to the accompanying drawings. The dimensions, materials, shapes, numbers, relative arrangements, and the like of the components described in the embodiments are not intended to limit the technical scope of the present invention unless otherwise specified. <Ausführungsform>

[0016] Here, based on the Fig. 1 and Fig. 2 an overview of a mobile robot 10 according to the present embodiment is given. Fig. Fig. 1 is a view showing an external appearance of the mobile robot 10, and Fig. Figure 2 is a diagram showing functional blocks included in the mobile robot 10. A main body portion 13 of the mobile robot 10 includes a portion mainly related to a flying motion of the mobile robot 10 and a portion mainly related to a walking motion of the mobile robot 10. That is, in the present embodiment, the mobile robot 10 is configured to realize the flying motion and the walking motion.

[0017] First, a structure related to flight motion will be described. A plurality of drive units 12 are arranged on the main body portion 13 via a plurality of bridge elements. Fig. In the example shown in Figure 1, four drive units 12 are attached to the main body portion 13, but as long as the flight of the mobile robot 10 is possible, the number of drive units 12 attached thereto is not limited to four, as long as there are multiple ones. Furthermore, in the present embodiment, when the mobile robot 10 is in a reference posture with respect to the contact surface (e.g., the ground or the like) FL, a rotor plane (see plane B to be described later in Fig. 5), which is formed by connecting the centers of the four drive units, is parallel to the contact surface FL, and the four drive units 12 are each arranged in rotational symmetry around the main body portion 13 on the plane B. In other words, the four drive units 12 are arranged on the plane B in line symmetry with respect to a predetermined center line or in point symmetry with respect to a predetermined point. Here, it should be noted that in the reference posture, all four leg portions 11 to be described later are in a predetermined state so that the main body portion 13 is not inclined with respect to the contact surface FL. It should also be noted that when the drive units 12 are individually designated, the reference numerals 12a to 12d are used.

[0018] The drive units 12 each include a propeller, which is a rotating blade, and an actuator for rotating the propeller. All four drive units 12 are of the same type, but the actuators in the respective drive units 12 can be controlled independently of each other. Therefore, it is possible to appropriately control the driving force achieved by each drive unit 12, thereby making it possible to appropriately control the flight attitude, flight speed, and the like of the mobile robot 10. As described later, even in assistive control when the mobile robot 10 performs a walking motion, the actuators in the respective drive units 12 can be controlled independently of each other. In addition, the mobile robot 10 is provided with a sensor (flight sensor) 15 required for its flight motion, sensors (contact sensors) 16 required for its walking motion, and a battery 17 (see Fig. 2) to supply drive energy to the sensors and actuator of each drive unit 12, and a control device to control the energy supply from the battery 17 to each actuator. The control device integrates two control units, a first control unit 100 and a second control unit 200, the details of which will be described later.

[0019] Next, a structure related to the walking motion will be described. The mobile robot 10 has leg sections 11 (four legs) configured to perform the walking motion. It should be noted that in the Fig. 1, four leg portions 11 are provided on the main body portion 13, but the number of leg portions 11 is not limited to four as long as walking motion is possible, and two or three leg portions 11 may be provided, or five or more leg portions 11 may be provided. Note that in a case where the leg portions 11 are individually designated, reference numerals 11a to 11d are used.

[0020] As an example for the leg sections 11, Fig. 1 shows a simple view of each leg portion 11. The leg portions 11 each include a ground contact portion that comes into contact with the ground when the mobile robot 10 performs a walking motion, a connecting portion relatively rotatably connected to the ground contact portion via a joint, a hip joint portion relatively rotatably connected to the connecting portion via a joint, and a plurality of actuators (not shown) that drive and control the rotation of each joint. The joint connected to the connecting portion is designed with respect to its rotation directions (i.e., rotation directions about a roll axis and a pitch axis) according to the assumed walking motion. Note that the configuration of each leg portion 11 is not limited to such an example.Furthermore, each hip joint section is connected to a bottom surface of the main body section 13 via a predetermined joint, allowing it to rotate relatively. This predetermined joint is configured to rotate about a yaw axis. The predetermined joint may also be configured to rotate about a roll axis and a pitch axis.

[0021] The leg portions 11 configured as described above are a structure that enables the walking motion of the mobile robot 10 while supporting the mobile robot's own weight against the contact surface FL in the walking motion of the mobile robot 10. Therefore, the four leg portions 11 function as support portions of the present invention to realize the walking motion included in the movement type motion. Moreover, unlike the flying motion, the movement of the mobile robot is performed in a state where at least one of the four leg portions 11 is in contact with the contact surface FL to support the main body portion 13. Therefore, the walking motion is also a form of motion included in the contact motion. <Steuereinheit des mobilen Roboters 10>

[0022] Next, the control configuration of the mobile robot 10 is determined using Fig. 2. The mobile robot 10 has a control device including a first control unit 100 and a second control unit 200. The control device is a computer with arithmetic processing means and a memory, and the second control unit 200 includes, as functional units, a detection module 210, a setting module 220, and an execution module 230. Each functional unit is formed by executing a predetermined control program in the mobile robot 10.

[0023] First, the first control unit 100 will be described. The first control unit 100 is a functional unit for performing walking motion and flying motion in the mobile robot 10 using the leg sections 11 and the drive units 12. That is, the first control unit 100 controls the actuators provided on the leg sections 11 for walking motion and further controls the drive units 12 for flying motion. The first control unit 100 controls the driving forces of the four drive units 12 based on environmental information, which is information related to the flying state of the mobile robot 10 and detected by the flight sensor 15.As such environmental information, for example, information about an angular velocity of the main body portion 13 detected by a gyro sensor corresponding to three axes (a yaw axis, a pitch axis, and a roll axis) may be used, an inclination or slant of the main body portion 13 detected by an acceleration sensor corresponding to the same three axes (not shown), and the like. The first control unit 100 performs feedback control using the environmental information detected by these sensors so that the inclination of the main body portion 13 of the mobile robot 10 is in a state suitable for flight. Further, the environmental information may include an azimuth angle indicating the orientation of the main body portion 13 (ie,the orientation of the main body section of the mobile robot 10) in the absolute coordinate system when the orientation of the earth's axis is set as a reference, and the azimuth angle can be detected by an azimuth angle sensor.

[0024] Here, in a case where the main body portion 13 of the mobile robot 10 is caused to fly forward, backward, left, and right, the first control unit 100 decreases the rotational speed of the actuator of a drive unit 12 in the traveling direction and increases the rotational speed of the actuator of a drive unit 12 on the opposite side to the traveling direction, so that the main body portion of the mobile robot 10 assumes a forward-leaning posture with respect to the traveling direction and thus travels in a desired direction. Also, in a case where the main body portion of the mobile robot 10 is caused to rotate and fly, the first control unit 100 provides the output of each propeller 21 according to its rotational direction based on the rotational direction of the main body portion 13 of the mobile robot 10.For example, when the main body portion 13 of the mobile robot 10 is rotated to the right, the first control unit 100 decreases the power of the actuator corresponding to the propeller rotating to the right and increases the power of the actuator corresponding to the propeller rotating to the left.

[0025] Furthermore, a walking motion performed by the first control unit 100 will be described. The first control unit 100 is also a functional unit that, when the mobile robot 10 walks, controls an actuator provided on each of the four leg portions 11 for walking. The first control unit 100 uses environmental information detected by the contact sensors 16, which indicates whether the ground contact portion of each leg portion 11 is in contact with the contact surface FL when the walking motion is performed. Note that, in the present embodiment, a predetermined walking control program for walking on the contact surface FL, which is used by the first control unit 100, uses detection values ​​of the contact sensors 16, reducing the acquisition of information about the surroundings of the mobile robot 10 as much as possible to make the walking control of the mobile robot 10 simpler and easier.

[0026] Specifically, the actuator provided at each joint of the leg portions 11 is provided with an encoder (not shown) that detects state quantities (the rotational position, rotational speed, and the like of the actuator's rotary shaft) related to each rotation state. Note that a different sensor may be used instead of the encoder. Then, the first control unit 100 performs feedback control of the actuators of the leg portions 11 based on the state quantities of each actuator detected by the actuator's encoder, so that the walking motion of the mobile robot 10 is realized according to a motion instruction given to the mobile robot 10. As described above, in the present embodiment, the feedback control of the actuators relies as little as possible on environmental information outside the robot.This allows the sensors to be attached to the mobile robot 10 to be omitted as far as possible and the walking control itself to be simplified.

[0027] Furthermore, during walking control, the contact sensors 16 detect whether the ground contact portions of the respective leg portions 11 are in contact with the contact surface FL or not. The fact that a leg portion 11 is not in contact with the contact surface FL means that the main body portion 13 of the mobile robot 10 is not supported by a reaction force from the contact surface FL via that leg portion 11. Therefore, if the main body portion 13 of the mobile robot 10 is not supported by the leg portion 11, the stability of the main body portion 13 may change, and in some cases, the possibility of the main body portion 13 tipping over increases. In such a case, in the present embodiment, the assist control is performed by the second control unit 200 (corresponding to the "assistance control for walking control" according to the present invention). <assistenzsteuerung>

[0028] The following describes the assistance control by the second control unit 200. The second control unit 200 has the detection module 210, the setting module 220, and the execution module 230, and these functional units work together to realize the assistance control. Here, Fig. 3 describes a change in the stability of the main body section 13 during the walking control (when the mobile robot 10 performs the walking movement). The upper part (a) of Fig. 3 shows a state in which the four leg portions 11 of the mobile robot 10 are in contact with the contact surface FL, and the lower part (b) shows a state in which one leg portion 11a among the four leg portions 11 is separated or removed from the contact surface FL. The state in which the leg portion 11a is separated from the contact surface FL is detected by the contact sensor 16 of the leg portion 11a. Here, it is assumed that the mobile robot 10 performs a walking motion while a workpiece W is mounted thereon.

[0029] Here, for the leg portions 11 whose ground contact portions are actually in contact with the contact surface FL, a closed area formed to encompass the contact points is defined as the actual support area SS. For example, the actual support area SS may be a polygonal area having the contact points as vertices. In this case, Fig. 3 (a) the actual support area SS is formed in a quadrangular shape, and in Fig. 3 (b), the actual support area SS is formed in a triangular shape. In addition, from the viewpoint of appropriately supporting the mobile robot 10, the actual support area SS may be formed in shapes different from those shown in Fig. 3 (a) and (b) are further reduced inward. Note that the second control unit 200 can determine the position of the contact point of each leg portion 11 from the detection value of each contact sensor 16 and the state (position) of the actuator of each leg portion 11 when its contact state is detected.

[0030] Then, when the mobile robot 10 performs walking control using the four leg sections 11, a position where the center of gravity of the mobile robot 10 should be during walking is given as a position command to the first control unit 100, and each leg section 11 is driven to follow the position command. At this time, the position of an ideal ZMP calculated from the trajectory or the like of the mobile robot 10 is defined as the target printing position PP. The load of the workpiece W carried by the mobile robot 10 is also considered for the target printing position PP. Then, during the walking control, as shown in Fig. 3 (a), when the target printing position PP is within the actual support range SS, the mobile robot 10 is stably supported by the four leg sections 11. On the other hand, as shown in Fig. 3 (b), the target pressure position PP is not within the actual support range SS, the mobile robot 10 is not stably supported by the three leg sections 11b, 11c, 11d. Therefore, the mobile robot 10 may tip over in this case.

[0031] Therefore, in the present embodiment, the four drive units 12 are used to generate an additional supporting force (assisting supporting force) required to prevent tipping that may occur when the target printing position PP deviates from the actual supporting surface SS in this way. The generation of the assisting supporting force is determined based on Fig. 4. The Fig. The state of the mobile robot 10 shown in Figure 4 is the same as that shown in Fig. 3(b), and the target pressure position PP is outside the actual support range SS. Here, when supporting the support force, a load to be borne by the leg sections 11b, 11c, 11d in actual contact with the contact surface FL is set. This load is a load to be borne by the leg sections 11b, 11c, 11d for the total load required for the movement of the mobile robot 10 to be supported, which should be shared by the leg sections 11b, 11c, 11d and the drive units 12. Therefore, the load can be appropriately set by taking into account the driving forces of the drive units 12 and the support forces of the leg sections 11 (the performances of the actuators installed in the leg sections 11b, 11c, 11d, their structural strength, etc.).In general, it is advantageous for a certain load to be applied via the leg portions 11b, 11c, 11d to generate an appropriate friction force so that the mobile robot 10 can stand stably on the contact surface FL, and therefore, it is not advantageous to unnecessarily reduce the load to be borne by the leg portions 11b, 11c, 11d. Then, the location where a resultant force F2 of the loads is generated by the leg portions 11b, 11c, 11d is defined as the support generation position P2. The support generation position P2 is determined as an optional position within the actual support range SS of the leg portions 11b, 11c, 11d.

[0032] Then, an assisting support force F1 is generated at the virtual support position P1, which is outside the actual support range SS. The virtual support position P1 is a position in a range corresponding to an actual support range formed when the supporting force is generated at the virtual support position P1 by the leg portions 11, that is, a position in an enlarged support range S1 in which the target pressure position PP is included when the enlarged support range S1 is formed by the contact points of the leg portions 11b, 11c, 11d and the virtual support position P1. The identification of the virtual support position P1 and the calculation of the assisting support force F1 are carried out using Fig. 5 and Fig. 6. The state of the mobile robot 10 in Fig. 5 is the same as in Fig. 4 shown.

[0033] In Fig. 5, three planes A to C are defined for explanation. Plane A is a plane containing the target pressure position PP and the support generation position P2 and extending in the vertical direction (the direction perpendicular to the contact surface FL). Plane B is a plane containing the centers of the four drive units 12 and is parallel to the contact surface FL. Plane C is a plane containing the center of gravity of the mobile robot 10 and is parallel to the contact surface FL. As shown in Fig. As can be seen from Figure 6, the driving forces of the drive units 12 act on plane B. The driving forces generate the supporting force F1 to support the load required for the movement of the mobile robot 10, which is associated with the walking motion. At this time, plane B formed by the drive units 12 is supported so that it is parallel to the contact surface FL.

[0034] Here, the virtual support position P1, where the supporting support force F1 is generated, is located on a straight line connecting the support position generation position P2, where the resultant force F2 of the loads is generated by the leg sections 11b, 11c, 11d, and the target pressure position PP. The reason for arranging the three points on a straight line is that the mobile robot 10 is less likely to lose its balance when the supporting force is assisted by the drive units 12. Therefore, as long as the balance of the mobile robot 10 is maintained within an allowable range, the three points do not necessarily need to be arranged on a straight line.Note that in the present embodiment, the three points are arranged on a straight line, and a line segment between the virtual support position P1 and the target printing position PP is defined as line segment A, and a line segment between the support generation position P2 and the target printing position PP is defined as line segment B. In such a case, F1 can be calculated according to the following Formula 1. F1:F2=Length of line segment B:Length of line segment A

[0035] From Formula 1, it follows that with increasing length of line segment A, the support of the mobile robot 10 can be supported while simultaneously reducing the supporting force. Therefore, in order to reduce the power of the drive units 12 that generate the supporting force, it is advantageous to set line segment A as the longest, i.e., at the position furthest from the target pressure position. Here, as shown in Fig. As shown in Figure 7, in the mobile robot 10, four drive units 12 are arranged from the main body portion 13 via bridge members 14. The distance from the center of symmetry of the mobile robot 10 to each drive unit 12 can be appropriately ensured by each bridge member 14. Since the resultant force of the driving forces by the drive units 12 is directly below each drive unit 12 at the position farthest from the center of gravity, arranging the drive units 12 via the bridge members as described above contributes to ensuring a longer length of the line segment A in Formula 1.

[0036] Here, support by the support force is discussed from a physical perspective. To simplify the explanation, it is assumed that the robot's flying body is in a static state and is not in contact with any object other than the contact surface FL. When considering dynamic states, in addition to the gravity acting on the mobile robot 10, the forces required for the desired movement must be taken into account. If the flying body is in contact with an object other than the contact surface FL, its contact force must also be considered. Fig. 6, the total sum of the reaction force (resultant F2) transmitted from the contact surface to the leg portions 11 and the virtual support force (assistive support force F1) assumed to be generated by the drive units 12 on the contact surface FL is equal to the gravity force, and therefore the following formula 2 holds. [Math. 1] ∑i=14fRi+∑i=1nfVi−mg=0 where fRi represents the reaction force transmitted to each leg section 11 and fVi represents the above-mentioned virtual support force.

[0037] Further, the total sum of the moment due to the reaction force (resultant force F2) transmitted from the contact surface to the leg portions 11 in contact therewith and the moment due to the virtual support force (assisting support force F1) assumed to be generated at the contact surface FL by the drive units 12 becomes zero, and thus the following formula 3 holds. [Math. 2] ∑i=14rRi×fRi+∑i=1nrVi×fVi=∑i=14rRi×fRi+∑i=14rri×frVi=0 where rRi represents the position of the ground contact portion of each leg portion, rVi represents the position where the above-mentioned virtual support force is generated (virtual support position P1), and rRi represents the position of each drive unit 12. In addition, frVi represents the driving force of each drive unit 12 required to generate the assisting support force.

[0038] Then put that in Fig. 2 sets the reaction force fRi transmitted to each leg portion 11, which satisfies Formula 1, Formula 2, and Formula 3. Further, the execution module 230 calculates the assist support force F1 satisfying Formula 1, Formula 2, and Formula 3, and adjusts the power of each drive unit so that the assist support force F1 is generated at the virtual support position P1. In addition, the detection module 210 detects the target pressure position PP at the time when the gait control of the mobile robot 10 is performed. The thus detected target pressure position PP is used to determine whether it is within the actual support range SS for the calculation according to Formula 1 and the like described above.

[0039] Fig. Fig. 8 shows the variation transitions of the inclination of the main body portion 13 of the mobile robot at the time when the mobile robot 10 is actually walking, in a case where assistance control is performed by the second control unit 200 (upper view (a)) and in another case where no assistance control is performed (lower view (b)). The roll axis and the pitch axis of the mobile robot 10 are axes lying on a plane parallel to the contact surface FL. As shown in Fig. As can be seen from Fig. 8, by performing the assistive control by the second control unit 200, the inclination change of the main body portion 13 is suppressed compared to the case where the assistive control is not performed, thereby improving the stability of the walking motion of the mobile robot 10. In addition, as described above, a stable walking motion is achieved, as shown in Fig. 8, although the number of sensors to be used is small because the use of environmental information for walking control of the mobile robot 10 is suppressed as much as possible. <Modifizierte Ausführungsform 1>

[0040] A modified example of the mobile robot 10 disclosed in the present application will be described with reference to Fig. 9. As shown by Fig. 6, the supporting support force F1 is a force for supporting the main body portion 13 of the mobile robot 10 in such a manner that the plane B is parallel to the contact surface FL. However, depending on the posture of the mobile robot 10, the output response of the drive units 12, or the like, there is a possibility that the posture of the mobile robot 10 deviates significantly, as shown in the upper part (a) of Fig. 9. Therefore, in the present modified embodiment, for example, the angle and angular velocity around the roll axis and pitch axis of the mobile robot 10 can be fed back to correct the target printing position PP. The angle and angular velocity around each axis are detected by a sensor (gyro sensor or the like) capable of detecting the angle and angular velocity.

[0041] As a result of the correction, for example, the target print position, which would originally be shifted to PP0, PP1 and PP2, shifts to PP0, PP1' and PP2' (see the lower part (b) of Fig. 9). In this case, the path actually traveled by the mobile robot 10 deviates from the path the mobile robot 10 was originally supposed to travel, but on the other hand, the posture of the mobile robot 10 is maintained in a more stable state. For this reason, the above-mentioned feedback processing can be considered useful in a case where there is a relatively large margin for adjusting the walking path. <Modifizierte Ausführungsform 2>

[0042] In the mobile robot 10, in addition to generating the assistive support force, the outputs of the drive units 12 can be feedback-controlled to control the posture of the main body portion 13. In this case, the drive units 12 overlap the drive forces required for assistive force generation and posture control, and the drive forces required for posture control are referred to as posture control drive forces. Furthermore, the mobile robot 10 can additionally drive the drive units 12 to further output the drive forces to apply an appropriate load to the contact surface FL to achieve posture stability during walking motion through its friction force, or conversely, to reduce the friction force with the contact surface FL to reduce the energy required for walking motion.The driving forces of the driving units 12 for adjusting the load on the contact surface FL are called self-weight balancing driving forces, and the load generated by the self-weight balancing driving forces on the contact surface FL is called self-weight balancing target.

[0043] Therefore, the following formula 4 applies. [Math. 3] case=∑i=14fRi+∑i=1nfVi−mg+∑i=14fcorri+∑i=14fcompadi−fweight+Δf where fcorri represents the driving force for posture control of each drive unit 12, fcompadi represents the driving force for balancing the dead weight of each drive unit 12, and fweight represents the target for balancing the dead weight. Furthermore, Δf represents a disturbance force.

[0044] In addition, the following formula 5 applies from the relationship of the moment around the center of gravity. [Math. 4 Mall=∑i=14rRi×fRi+∑i=14rri×fcorri+ΔM=∑i=14rRi×fRi+∑i=14rVi×fVi+∑i=14rri×fcorri+ΔM where ΔM represents a disturbance torque.

[0045] As can be seen from Formulas 1 to 5, the assist control for generating the assist support force can be performed based on Formulas 1 to 3 by adding posture feedback control and self-weight balance control, and thus, in the mobile robot 10, it is possible to easily select the control implementation according to the purpose of each control. However, it should be noted that when posture feedback control or self-weight balance control is added to the assist control, the actual virtual support position P1, the actual assist support force F1, the actual support generation position P2, and the actual resultant force F2 change. <Andere Ausführungsformen>

[0046] First, based on Fig. 10 describes a first form of support state by the leg sections 11 during the walking movement of the mobile robot 10. It should be noted that in Fig. 10 the walking movement is performed on a contact surface that is not a flat surface, but is in a so-called uneven ground condition. The upper part (a) of Fig. 10 shows a state in which the main body portion 13 of the mobile robot 10 is supported using all four leg portions 11. Moreover, the middle part (b) shows a state in which three leg portions 11 of the four leg portions 11 are used to support the main body portion 13 of the mobile robot 10, and specifically, the leg portion 11a is separated from the contact surface, and the main body portion 13 is supported by the other leg portions 11b, 11c, 11d. Furthermore, the lower part (c) shows a state in which the main body portion 13 of the mobile robot 10 is supported using two leg portions 11 among the four leg portions 11, specifically, the leg portions 11a, 11c are separated from the contact surface, and the main body portion 13 is supported by the other leg portions 11b, 11d.

[0047] The state in which the main body portion 13 is supported by the four leg portions 11 is the most stable state, but in the case where the contact surface is in the uneven ground state as in the present embodiment, there is a possibility that the target pressing position PP deviates from the actual support range SS due to a tilt or skew of the mobile robot 10 or the like. In such a case, the above-described assist control for walking control can be executed by the second control unit 200. This also applies to the case where the device is supported by three leg portions 11.

[0048] Here is how in Fig. As shown in Figure 10(c), in the case of support by two leg portions 11, the actual support area SS formed by the leg portions 11b, 11d in contact with the contact surface is a straight line area connecting their respective contact points. In such a case, when the target pressing position PP is located on the straight line, it is determined that the target pressing position PP is within the actual support area SS, and when the target pressing position PP deviates from the straight line, it is determined that the target pressing position PP is not within the actual support area SS. Then, in the latter case, the assist control for the gait control can be executed by the second control unit 200 described above.

[0049] The walking motion of the mobile robot 10 does not necessarily need to be performed using the four leg sections 11. For example, depending on the shape and inclination of the contact surface, two leg sections 11a, 11c of the four leg sections 11 may always be kept separate from the contact surface, and the remaining two leg sections 11b, 11d may be used for walking. That is, the walking motion should be performed using the number of leg sections most suitable for the nature of the contact surface. If the mobile robot 10 cannot be stably supported by these leg sections, assist control for the walking control should be performed by the second control unit 200 described above.

[0050] Next, Fig. 11 describes a second form of support state by the leg sections 11 at the time of walking movement of the mobile robot 10. The upper part (a) of Fig. 11 shows a state in which the main body portion 13 of the mobile robot 10 is supported using all four legs 11 and an end effector 20, which originally has a holding or grasping mechanism for holding or grasping an object. The number of contact points for supporting the main body portion 13 is increased by the contact between the end effector 20 and the contact surface, so that the actual support area SS can be enlarged. This increases the probability that the target pressure position PP falls within the actual support area SS, thereby achieving a more stable walking motion. Even in such a case, when the target pressure position PP deviates from the actual support area SS, the assistance control for gait control can be performed by the second control unit 200 described above.

[0051] Furthermore, the middle part (b) discloses a state in which the main body portion 13 of the mobile robot 10 is supported by an object 20a gripped or held by the end effector 20 in addition to all four leg portions 11. In this case, an actual support region SS is formed by a contact point between the object 20a held by the end effector 20 and the contact surface. For example, when the mobile robot 10 walks with the object 20a, a stable walking motion can be achieved by utilizing the object. Even in such a case, when the target pressure position PP deviates from the actual support region SS, the assist control for the walking control can be performed by the second control unit 200 as described above.

[0052] Furthermore, the lower part (c) discloses a state in which the main body portion 13 of the mobile robot 10 is supported by an auxiliary support portion 11e, in addition to two leg portions 11c, 11d among the four leg portions 11. Unlike the leg portions 11, this auxiliary support portion 11e is not directly used for walking motion but is configured to support the main body portion 13 during walking motion. The auxiliary support portion 11e is a structure that does not have a joint and an actuator for driving the joint as in the leg portions 11, but is configured to maintain contact with the contact surface by applying a certain load to the contact surface. In this case, too, an actual support area SS is formed by a contact point between the auxiliary support portion 11e and the contact surface.The supporting force of the auxiliary support portion 11e may be weaker than the supporting force of the leg portions 11 in some cases, but comparing, for example, the case of walking with the two leg portions 11c, 11d with the case of walking with the auxiliary support portion 11e added, the actual supporting area SS can be increased in the latter case, thereby realizing a stable walking motion. Even in such a case, the assist control for gait control can be performed by the second control unit 200 as described above when the target pressure position PP deviates from the actual supporting area SS. [List of reference symbols]

[0053] 10 ... mobile robot; 11, 11a, 11b, 11c, 11d ... leg sections; 11e ... auxiliary support section; 12, 12a, 12b, 12c, 12d ... drive units; 13 ... main body section; 14 ... bridge element; 15 ... flight sensor; 16 ... contact sensors; 17 ... battery; 20 ... end effector; 20a ... object, 100 ... first control unit; 200 ... second control unit; FL ... contact surface; PP ... target printing position; SS ... actual support area; P1 ... virtual support position; P2 ... support generation position; F1 ... assistant support force; F2 ... resultant force. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2018-000015

[0003] WO 2016 / 193666

[0003] JP 6733965

[0003] < / assistenzsteuerung>

Claims

[1] Mobile robot comprising: a main body portion having a plurality of drive units each configured to generate a driving force by driving a rotating vane; a plurality of support portions provided on the main body portion and configured to come into contact with a predetermined contact surface to support at least a part of the main body portion; a first control unit configured to perform movement control for moving the main body portion on the predetermined contact surface by the plurality of support portions while the main body portion is supported by the plurality of support portions; and a second control unit configured to perform assistance control for the motion control by the first control unit using part or all of the plurality of drive units; wherein in the assist control, when a target pressing position relating to the transition of a center of gravity of the main body portion in the motion control is not within an actual support range in which the main body portion is actually supported by predetermined support portions in contact with the predetermined contact surface among a plurality of support portions, the second control unit drives part or all of the plurality of drive units to generate an assisting support force outside the actual support range that assists a shortage of a support force required for the motion control. [2] The mobile robot according to claim 1, wherein the second control unit comprises: a detection module configured to detect the target print position; a setting module configured to set a support generation position at which the support force is generated by the predetermined support portions within the actual support range; and an execution module configured to identify, based on the target printing position and the support generation position, a virtual support position on the predetermined contact surface outside the actual support area with which the predetermined support portions are not in contact, calculate the assisting support force at the virtual support position, and drive part or all of the plurality of drive units to generate the assisting support force. [3] The mobile robot according to claim 2, wherein the virtual support position is identified by the execution module such that the target printing position is included in an enlarged support area defined by the actual support area and the virtual support position. [4] The mobile robot according to claim 3, wherein the virtual support position is on the opposite side of the support generation position from the target pressure position, and the virtual support position, the target pressure position and the support generation position are arranged on a straight line. [5] The mobile robot according to claim 4, wherein the virtual support position is identified as a position farthest from the target printing position within a range that can be set based on an arrangement of the plurality of drive units. [6] The mobile robot according to any one of claims 1 to 5, wherein, in a case where the number of predetermined support portions in contact with the predetermined contact surface among a plurality of support portions is three or more, the actual support region is a polygonal region formed by connecting contact points between each of the predetermined support portions and the predetermined contact surface; and in a case where the number of predetermined support portions in contact with the predetermined contact surface among the plurality of support portions is two, the actual support region is a rectilinear region formed by connecting contact points between each of the two predetermined support portions and the predetermined contact surface. [7] The mobile robot according to any one of claims 1 to 5, wherein the plurality of drive units are arranged with respect to the main body portion in a line symmetry or point symmetry when viewed from the direction of gravity of the main body portion. [8] The mobile robot according to any one of claims 1 to 5, wherein the plurality of support portions are a plurality of leg portions attached to the main body portion so as to be capable of bearing the weight of the main body portion. [9] The mobile robot according to claim 8, wherein the plurality of support portions further comprises a holding portion capable of holding an object, or the object held by the holding portion so as to come into contact with the predetermined contact surface.

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