Non-singular gravity balance force feedback master manipulator operation arm based on man-machine interaction

Abstract

The invention provides a non-singular gravity balance force feedback master manipulator operation arm based on human-computer interaction, and relates to the technical field of medical robots. The operation arm comprises a supporting base, a translation guide mechanism, a non-singular connecting arm, a rotating wrist mechanism and a holding interaction assembly. The non-singular connecting arm adopts a geometric structure which is bent inwards, so that singular poses with parallel three axes in the movement process of the mechanism are effectively avoided; the balance assembly is arranged at the near end of the non-singular connecting arm, and passive gravity balance of a tail end load is achieved through a balance weight. The rotating wrist mechanism is driven by a motor and provides three-degree-of-freedom force feedback based on impedance control; the holding interaction assembly is internally provided with a symmetrical double-path wiring structure to prevent cable loss, and is integrated with a repositioning and master hand enabling button. Through singular point elimination and gravity compensation, the operation inertia and the fatigue feeling are reduced, and the stability of teleoperation and the high fidelity of force sense feedback are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of medical robots, and particularly relates to a non-singular gravity balance force feedback master operating arm based on human-computer interaction. BACKGROUND

[0002] As the core input device of a robot teleoperation system, the master operating arm is a key link for realizing accurate mapping of the action intention of a doctor to surgical instruments, and its performance directly determines the safety and operation precision of remote surgery. In order to pursue human-like flexibility and a wide operating space, a modern master operating arm usually adopts a multi-degree-of-freedom (usually 6 or 7) serial or parallel configuration to reproduce the complex motion of a human arm and wrist. In the field of surgical robots, the master operating arm not only needs to have high-fidelity and low-delay motion tracking capability, but also needs to feed back the interaction force of the from-end environment to the operator in real time through force feedback technology, so as to build an immersive force sense of presence and assist the doctor to complete fine cutting, suturing and other high-difficulty operations.

[0003] However, the existing multi-degree-of-freedom master operating arm still faces two core technical problems to be solved in actual application: one is the singular pose problem of the mechanism, when the operating arm moves to a specific position, the Jacobian matrix becomes rank-deficient, resulting in loss of motion freedom in a specific direction, causing joint speed tending to infinity, system jitter and even force sense "hollow feeling" and other out-of-control phenomena, which seriously misleads the judgment of the operator; the other is the gravity load and operation fatigue problem, the gravity moment generated by the links and joints of the master operating arm will form a continuous static load, and the operator needs to constantly exert force to maintain the pose, which not only leads to muscle fatigue after long-time operation, but also amplifies muscle tremor due to the resistance to gravity, interferes with the real force sense feedback, and reduces the positioning accuracy. Therefore, how to design a master operating arm that can completely eliminate singular points from the configuration and realize full-degree-of-freedom static gravity balance and high-quality force feedback has become a key demand to improve the teleoperation experience of surgical robots. SUMMARY

[0004] In view of the problems in the prior art that the master operating arm is prone to singular configuration at a specific pose, resulting in motion out-of-control, the self-gravity load of the master operating arm causes operator fatigue, and the force sense feedback is interfered by static force, resulting in reduced sense of presence, the application provides a non-singular gravity balance force feedback master operating arm based on human-computer interaction.

[0005] This invention is implemented as follows: a non-singular gravity balance force feedback master hand operating arm based on human-computer interaction, characterized in that it comprises: a support base; a translational guide mechanism, one end of which is connected to the support base to provide at least two translational degrees of freedom; a rotating wrist mechanism, including multiple series-connected rotating joints to provide multiple rotational degrees of freedom, and the end of the rotating wrist mechanism is provided with a gripping interaction component; and a non-singular connecting arm, disposed between the translational guide mechanism and the rotating wrist mechanism, the non-singular connecting arm having an inwardly bent geometric configuration to avoid the three rotating joint axes being parallel to each other when the master hand operating arm moves in the entire workspace.

[0006] In the above technical solution, preferably, it further includes: a balancing component, disposed at the proximal end of the non-singular connecting arm, for counteracting the static load of the rotating wrist mechanism and the gripping interaction component by generating a gravitational torque.

[0007] In the above technical solution, preferably, the balancing component includes a housing covering the outside of the mechanism and a counterweight disposed inside the housing.

[0008] In the above technical solution, preferably, the rotating wrist mechanism is equipped with at least three power elements, and the power elements provide force feedback to the grip interaction component with respect to the direction of rotational degree of freedom through impedance control.

[0009] In the above technical solution, preferably, the inward bending angle of the non-singular connecting arm is 45 degrees.

[0010] In the above technical solution, preferably, the translational guiding mechanism includes a first articulated arm and a corner joint, which rotate around a first axis and a second axis arranged vertically to achieve translational guidance.

[0011] In the above technical solution, preferably, the grip interaction component is provided with a repositioning trigger and a master hand enable trigger; wherein, the repositioning trigger is used to control the braking device of the operating arm to achieve repositioning; the master hand enable trigger is used to control the operating arm to enter or exit the force feedback motion mode.

[0012] In the above technical solution, preferably, the grip interaction component has a wiring channel inside, and the cable is divided into at least two strands and arranged symmetrically inside the grip interaction component to prevent damage to the cable caused by rotation or clamping actions.

[0013] In the above technical solution, preferably, each moving component of the main hand operating arm is covered with an electromagnetic shielding shell.

[0014] In the above technical solution, preferably, the motion is transmitted internally through a helical gear pair in the rotating wrist mechanism.

[0015] This application provides a multi-degree-of-freedom non-singular gravity balance force feedback master arm based on human-computer interaction, which has the following beneficial effects: First, regarding kinematic configuration, this application effectively avoids singularities in the main arm's workspace by designing the pitch lever with a special inward-bending configuration, ensuring the continuity and stability of the mechanism's movement from a topological perspective. Second, regarding gravity compensation and user experience, a balancing mechanism consisting of the pitch lever, its easily removable casing, and a counterweight assembly enables precise static balancing of the rear wrist assembly and grip rotation mechanism, minimizing the inertial effects felt by the operator during movement and providing a comfortable and stable operating environment. Third, regarding force feedback and interactive control, this application utilizes three motors controlling wrist posture rotation to provide the operator with high-fidelity force feedback in three rotational degrees of freedom along three axes, effectively counteracting system motion friction and inertia, thus enhancing the sense of presence during operation. Furthermore, regarding structural protection and reliability, this application features easily removable housings covering the base, translational linkage, pitch mechanism, and wrist assembly, effectively preventing internal electromagnetic interference and ensuring accurate signal transmission. Simultaneously, its gripping rotation mechanism employs a symmetrically distributed cable routing slot and channel design, effectively preventing cable wear or breakage during frequent rotation or opening / closing movements. Finally, by integrating an encoder position detection system and a brake device, this application achieves precise posture feedback and convenient repositioning, enabling efficient control of bedside surgical instruments and completion of complex surgical procedures from the arm. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main hand operating arm in this invention; Figure 2 This is a schematic diagram of the internal structure of the main hand operating arm in this invention; Figure 3 This is a schematic diagram of the internal structure of the easily detachable shell on the pitch rod in this invention; Figure 4 This is a schematic diagram of the internal structure of the rear end of the second articulated arm in this invention; Figure 5 This is a schematic diagram of the internal structure of the first joint arm of the wrist in this invention; Figure 6 This is a schematic diagram of the internal structure of the second joint arm of the wrist in this invention; Figure 7 This is a schematic diagram of the structure of the end-grip interaction component in this invention; Figure 8 This is a schematic diagram of the working state structure of the main hand operating arm in this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] This invention provides a non-singular gravity balance force feedback master arm based on human-computer interaction. To further illustrate the structure of this invention, a detailed description is provided below in conjunction with the accompanying drawings: Please see Figure 1 , Figure 2 and Figure 8 This embodiment provides a multi-degree-of-freedom non-singular gravity balance force feedback master arm based on human-computer interaction. The master arm mainly consists of five parts: a support base, a translational guide mechanism, a non-singular connecting arm, a rotating wrist mechanism, and a gripping interaction component. The support base, as the fixed support component of the entire machine, is mainly formed by bolting together a master hand translational base 1 and a master hand translational base shell 2. The translational guide mechanism is connected to the support base and provides at least two translational degrees of freedom, specifically achieving translational guidance of the operating space through rotational motion of a first axis and a second axis. The translational guide mechanism includes a first articulated arm and a corner joint, which rotate around the vertically arranged first and second axes respectively to achieve translational guidance. Specifically, the first articulated arm consists of a connecting rod 4, an upper easily detachable shell 3, and a lower easily detachable shell 5, which are connected to the support base through a first rotating shaft and bearings, and rotate around the first axis. The corner joint consists of a second joint corner 6 and a second joint corner easy-to-remove shell 7. It is connected to the first joint arm through the first rotating shaft and rotates around the second axis.

[0019] Please see Figure 3 and Figure 4 Between the translational guiding mechanism and the rotating wrist mechanism, a key non-singular connecting arm and a corresponding pitch balancing mechanism are provided. The pitch balancing mechanism includes the front end of the second articulated arm, which is fixedly composed of a front pitch rod 8, a lower removable housing 9, and an upper removable housing 10, and rotates around a third axis. To eliminate the singular poses commonly found in surgical robot teleoperation, the non-singular connecting arm (i.e., the rear end of the second articulated arm) in this embodiment adopts a geometric configuration with an inwardly bent preset angle. This connecting arm is fixedly composed of a rear pitch rod 11 and a pitch rod removable housing 12. Specifically, one end of the non-singular connecting arm is fixed to the front end of the second articulated arm, and the other end is bent inward at 45 degrees to connect to the subsequent rotating wrist mechanism. This 45-degree inward bending topology design, from a geometric logic perspective, avoids the occurrence of singular points where any three rotational joint axes are parallel to each other when the mechanism moves around axis I to axis VI. This ensures that the Jacobian matrix of the main arm is non-rank deficient throughout the entire workspace, thereby guaranteeing the dynamic stability and high fidelity of force feedback during operation.

[0020] In this embodiment, the inward bending configuration of the non-singular connecting arm breaks the geometric constraint that axes IV and VI are collinear or parallel to other axes in specific poses in traditional serial six-degree-of-freedom mechanisms by changing the kinematic topology of the mechanism. Although the preferred angle in this application is 45°, in practical applications, non-singular characteristics can be effectively achieved within the range of 30° to 60°. From a mathematical derivation perspective, the Jacobian matrix of the manipulator arm... J This reflects the mapping relationship between joint space velocity and end-effector Cartesian space velocity; singular poses occur in... The moment; by introducing a preset bending angle. a When constructing the forward kinematic equations of the mechanism, the axis direction vectors, which were originally on the same straight line, are forcibly decoupled. Specifically, when establishing the DH parameter table and its transformation matrix, the original equations, which only consisted of joint variables, are now decoupled. The determined trigonometric function components are introduced with respect to a fixed angle. a Related and The coupling term modulates the trigonometric function terms, which would otherwise easily lead to matrix rank deficiency, through the bias coefficient. Calculation results show that when the angle is between 30° and 60°, even though axes IV and VI are physically parallel, the projections of the rotation axes of each joint in Cartesian space cannot simultaneously satisfy the linear dependence condition due to the bending offset. This ensures that the Jacobian matrix always remains full rank, fundamentally eliminating singular solutions at the wrist. Furthermore, the choice of this angle range balances the coverage of the working envelope with the equilibrium of structural forces: if the angle is too small, the singularity elimination effect will be significantly weakened at edge poses; if the angle is too large, it will excessively compress the effective range of motion of the wrist and increase the joint torque load. Therefore, the bending design of 30° to 60° achieves the optimal balance between kinematic performance and dynamic stability while ensuring no singular characteristics throughout the working space.

[0021] To improve operational comfort and eliminate the static load sensation caused by gravity, this embodiment incorporates a balancing component at the proximal end of the non-singular connecting arm. This balancing component is a counterweight 102 integrated within the easily removable housing 10 on the pitch lever. The housing 101 and the counterweight 102 are joined by adhesive or other bonding methods to form the front-end assembly of the second joint. This balancing component, through a rational mass distribution design, provides static balance to the rear end of the second joint arm, the first and second wrist joints, and the end-effector gripping interaction assembly. This passive counterweight method eliminates the need for the operator to exert additional force to overcome the device's own gravitational torque, significantly reducing fatigue during prolonged surgical procedures and effectively enhancing the sense of force presence.

[0022] Please see Figure 5 and Figure 6The wrist mechanism is connected to the end of a non-singular connecting arm, providing fourth, fifth, and sixth rotational degrees of freedom through multiple series of rotating joints. Specifically, the rear end of the second joint arm is connected to a motor 14 via a motor frame 13. The output shaft of the motor engages with a wrist lever 16 via a rotation shaft 15, forming a first wrist joint arm that rotates around the fourth axis. The first wrist joint arm is further fitted with a motor 18 via a motor frame 17, and drives a wrist rotation lever 20 via a connecting shaft 19 and a pair of meshing helical gears, forming a second wrist joint arm that rotates around the fifth axis. The end of the second wrist joint arm is also connected to a gripping interaction component via a motor frame 21, a motor 22, and another set of helical gears, allowing it to rotate around the sixth axis as a third wrist joint arm. In this structure, the three motors controlling the wrist posture rotation, based on offsetting the friction and inertia of the mechanism's motion, provide force feedback information to the operator in the directions of the three rotational degrees of freedom (axis IV, V, and VI) through an impedance control algorithm. This active force feedback design allows users to perceive the environmental forces from the surgical instruments at the end of the device.

[0023] To achieve precise posture tracking and safe control, this embodiment integrates a complete position detection device and braking device into the translational guiding mechanism and pitch balancing mechanism. Specifically, encoders 23 are equipped on the motion joints around shafts I, II, and III, all connected via a synchronous belt drive system. Taking shaft I as an example, the synchronous belt pulley teeth are fixed to the first rotating shaft 24. The synchronous belt 25 drives the synchronous belt pulley teeth, thereby rotating the encoder output shaft and encoder 23 to achieve real-time acquisition of angle information. The detection principle for shafts II and III is the same, using corresponding synchronous pulley sets and encoder frames to achieve posture feedback. At the same time, each encoder output shaft passes through a brake 25, which acts as a braking device. It can lock the output shaft according to control commands, thereby achieving physical locking and braking of the corresponding joint axis.

[0024] Furthermore, in this embodiment, the master arm is covered with electromagnetic shielding shells for each moving component, including a master arm translational base shell, an easily removable shell on the upper link, an easily removable shell on the lower link, an easily removable shell on the second joint rotation angle, an easily removable shell on the lower pitch lever, an easily removable shell on the pitch lever, an easily removable shell on the wrist lever, and an easily removable shell on the wrist rotation lever. These shells are connected to the internal structural components by bolts, which not only facilitates maintenance and disassembly but, more importantly, effectively shields against internal and external electromagnetic interference, ensuring the stability and safety of signal transmission in the surgical environment.

[0025] The end effector (i.e., the grip rotation mechanism) serves as the core of the interaction directly contacted by the operator, integrating complex mechanical transmissions and function buttons. Please refer to [link / reference]. Figure 7The gripping interaction component includes an opening and closing assembly and a handle 26. The opening and closing assembly consists of an opening and closing base 27, an opening and closing flap 28 mounted thereon, and a linkage slider mechanism that drives the opening and closing flap to reciprocate. Specifically, the opening and closing slider is placed in a groove in the opening and closing base and is hinged to the opening and closing flap 28 via an opening and closing linkage 29. When the operator drives the opening and closing flap 28 to rotate around the pin axis, the opening and closing linkage 29 drives the opening and closing slider to move, thereby simulating the clamping action of a surgical instrument. The handle is equipped with a repositioning button and a master hand button 30. The repositioning button is embedded in the groove of the handle through its columnar structure and is used to control the brakes of the aforementioned three joint axes to lock or release, thereby allowing the operator to adjust the position of the master hand in the operating space without changing the position of the slave instrument. The master hand button is connected to the handle through a columnar bolt and spring structure and is used to control the release of the three brakes and the enabling of the three motors, thereby activating the force feedback motion mode of the master hand operating arm.

[0026] To address the characteristics of medical robots involving prolonged rotation and high-frequency clamping, the gripping interaction component in this embodiment employs a unique anti-breakage wiring design. The opening and closing base features symmetrically distributed left and right wiring slots 31, a front wiring channel, and a rear wiring channel. The electrical signals and power cables from the repositioning button and main hand button at the handle are split into two strands before entering the opening and closing base. These strands are placed in the left and right slot contours via the front wiring channel and then converge along the rear wiring channel into the wrist rotation rod. This dual-path symmetrical wiring effectively prevents the cables from being squeezed, broken, or worn during large-angle rotations in the VI direction of the gripping rotation mechanism or during frequent clamping actions of the opening and closing flaps, ensuring high reliability of signal transmission.

[0027] In summary, this embodiment achieves a surgical robot master arm with high-fidelity force feedback, low motion inertia, and no singularity interference by employing a non-singular connecting arm bent inward at 45 degrees, a pitch balancing mechanism with integrated counterweights, a force feedback wrist mechanism driven by three motors, and a grip interaction component with a precision wiring structure. This multi-degree-of-freedom configuration design ensures the operator receives the most comfortable and stable movement experience while accurately replicating their movement intentions, thereby enabling precise control of the arm to perform delicate operations in complex medical surgical teleoperation tasks.

[0028] Furthermore, the inward bending geometry of the non-singular connecting arm, besides avoiding the rank deficiency of the Jacobian matrix, essentially reshapes the effective working envelope of the manipulator, enabling a better distribution of mechanical stiffness within a limited operating space. This effectively avoids the minute vibrations caused by abrupt stiffness changes at the edges of traditional serial manipulators, significantly improving positioning stability in delicate surgeries. The coupling design of the counterweight component and the easily removable shielding shell achieves static balance while its physical mass distribution cleverly acts as a mechanical filter, absorbing and attenuating the minute resonances generated by the motor under high-frequency impedance control, thus providing the operator with a purer, noise-free force-sensing interaction. The symmetrical dual-path wiring design inside the grip interaction component, besides preventing physical circuit breaks, uses the symmetrical arrangement of cables to physically cancel out local electromagnetic field fluctuations caused by current, reducing common-mode interference of sensor signals. This electromagnetic self-compatibility characteristic has extremely high clinical value in precision medical sensing environments. The synergy between the three-motor impedance control and the multi-joint brake system not only achieves repositioning, but also provides a "virtual limit" function through the flexible mapping of the motors. When the safe operating range is exceeded, the algorithm can give the operator a tactile damping warning, thus essentially building an active human-machine interaction safety barrier.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-singular gravity balance force feedback master manipulator based on human-machine interaction, characterized in that, The application relates to a master-slave manipulator, which comprises the following parts: a support base; a translational guide mechanism connected to the support base at one end and used for providing at least two translational degrees of freedom; a rotational wrist mechanism comprising a plurality of serial rotational joints and used for providing a plurality of rotational degrees of freedom, and the rotational wrist mechanism is provided with a holding interactive assembly at the end thereof; a non-singular connecting arm arranged between the translational guide mechanism and the rotational wrist mechanism, wherein the non-singular connecting arm has an inwardly bent geometric configuration, so that the master-slave manipulator can avoid the situation that three rotational joint axes are parallel to each other when the master-slave manipulator moves in the whole workspace.

2. The non-singular gravity balance force feedback master manipulator arm based on human-machine interaction according to claim 1, characterized in that, The application further comprises: a balancing assembly arranged at the proximal end of the non-singular connecting arm and used for offsetting the static load of the rotational wrist mechanism and the holding interactive assembly by generating a gravity moment.

3. The non-singular gravity balance force feedback master manipulator arm based on human-machine interaction according to claim 2, characterized in that, The balancing assembly comprises a shell wrapped outside the mechanism and a counterweight arranged inside the shell.

4. The human-machine interaction based non-singular gravity balance force feedback master manipulator arm of claim 1, wherein, The rotational wrist mechanism is provided with at least three power elements, and the power elements provide force feedback about the rotational degrees of freedom for the holding interactive assembly through impedance control.

5. The human-machine interaction based non-singular gravity balance force feedback master manipulator arm of claim 1, wherein, The inwardly bent angle of the non-singular connecting arm is 45 degrees.

6. The human-machine interaction based non-singular gravity balance force feedback master manipulator arm of claim 1, wherein, The translational guide mechanism comprises a first joint arm and a rotation angle joint, which rotate about a vertically arranged first axis and a second axis respectively to realize translational guidance.

7. The human-machine interaction based non-singular gravity balance force feedback master manipulator arm of claim 1, wherein, The holding interactive assembly is provided with a repositioning trigger and a master-slave enabling trigger; the repositioning trigger is used for controlling the brake device of the master-slave manipulator to realize repositioning; and the master-slave enabling trigger is used for controlling the master-slave manipulator to enter or exit the force feedback motion mode.

8. The human-machine interaction based non-singular gravity balance force feedback master manipulator arm of claim 1, wherein, A wiring channel is arranged inside the holding interactive assembly, and cables are divided into at least two strands and symmetrically arranged inside the holding interactive assembly, so as to prevent the cables from being damaged by rotating or clamping actions.

9. The human-machine interaction based non-singular gravity balance force feedback master manipulator arm of claim 1, wherein, An electromagnetic shielding shell is arranged outside each motion component of the master-slave manipulator.

10. The non-singular gravity balance force feedback haptics-based master manipulator arm of claim 1, wherein, Movement transmission is realized through a helical gear pair inside the rotational wrist mechanism.

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