A robot for welding automobile parts

Abstract

This invention belongs to the field of welding equipment technology, and particularly relates to a robot for welding automotive parts. It includes a robotic arm body and a mounting plate installed at the end of the robotic arm body. It also includes two symmetrically arranged clamping arms, each positioned below the mounting plate. Removable electrode welding heads are mounted on the opposite sidewalls of the two clamping arms. The mounting plate is equipped with a drive mechanism for moving the two clamping arms. Two support sleeves are respectively fixed to the opposite sidewalls of the two clamping arms, and U-shaped pressure-holding blocks are slidably connected to the inner walls of the two support sleeves. This invention can effectively reduce the adverse effects of high springback on weld joints in automotive stamping parts, eliminate welding porosity and spatter defects, improve joint forming quality, reduce electrode welding head end-face collapse, extend electrode life, and achieve adaptive pressure holding after welding, further ensuring the structural strength and stability of the weld joint.

Description

Technical Field

[0001] This invention belongs to the field of welding equipment technology, and in particular relates to a robot for welding automotive parts. Background Technology

[0002] With the development of new energy vehicles, automated production equipment has been widely used. For example, welding robots are widely used in the automated welding of automotive stamping parts. They can complete welding operations for workpieces such as door sill beams, doors, and body structural parts, realizing continuous and standardized operations for mass production and improving the welding efficiency and assembly consistency of automotive parts.

[0003] Aluminum alloy stamped parts are common components in new energy vehicles, such as door sill beams, inner door panels, and body longitudinal beams. When welding them, resistance welding is usually used, which involves clamping the workpiece with opposing electrodes and applying electricity. The workpiece is then welded by relying on electrode pressure and contact resistance to generate heat. However, in actual operation, aluminum alloy stamped parts have a low elastic modulus and large springback after stamping. Differences in assembly fit can also cause springback in the workpiece, which can create additional tensile stress on the hot weld joint. This can easily lead to internal defects in the weld joint, reduce weld strength, and increase the likelihood of defective weld joints. Although extending the electrode pressure time can improve the solidification strength of the weld joint and reduce the impact of springback in aluminum alloy stamped parts, the electrodes heated by electricity will experience accelerated end face collapse under continuous high pressure, affecting the lifespan of the electrodes. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a robot for welding automotive parts.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a robot for welding automotive parts, comprising a robotic arm body and a mounting plate installed at the end of the robotic arm body, and further comprising: Two symmetrically arranged clamping arms are both located below the mounting plate. Removable electrode welding heads are installed on the opposite sidewalls of the two clamping arms. The mounting plate is equipped with a drive mechanism to drive the two clamping arms to move. Two support sleeves are fixed to the opposite side walls of the two clamping arms respectively. The inner walls of the two support sleeves are slidably connected with U-shaped pressure holding blocks, and a square spring is fixed between the U-shaped pressure holding blocks and the side walls of the clamping arms. The electrode welding head is located inside the U-shaped pressure holding block. An extrusion venting unit is disposed inside the U-shaped pressure holding block, and the extrusion venting unit is used to expel air from the welding area by extrusion.

[0006] Preferably, the drive mechanism includes a housing detachably mounted on the bottom of the mounting plate, both clamping arms being slidably connected to the inner wall of the housing, a lead screw drive assembly being mounted on the side wall of the housing, and the lead screw drive assembly driving the two clamping arms to move along the inside of the housing, the lead screw drive assembly being electrically connected to the control end of the robotic arm body.

[0007] Preferably, the extrusion venting unit includes a pressure shaft disposed inside the U-shaped pressure holding block, with sliders rotatably connected to both ends of the pressure shaft. The two side walls of the U-shaped pressure holding block are provided with strip-shaped holes that match the sliders, and the sliders are slidably disposed inside the strip-shaped holes. The clamping arm is equipped with a pulling mechanism that drives the sliders to move, and the U-shaped pressure holding block is equipped with a reset assembly connected to the sliders.

[0008] Preferably, the retraction mechanism includes a rewind box fixed to the side wall of the clamping arm. A rotating shaft is rotatably connected inside the rewind box, and two rewind wheels are fixedly sleeved on the shaft wall. The rewind wheels wind and wind up steel wire. A motor is fixed to the side wall of the rewind box. The end of the steel wire away from the rewind wheel slides through the wall of the strip hole and is fixedly connected to the side wall of the slider. The motor is electrically connected to the control end of the robotic arm body. A tensioning component corresponding to the steel wire is installed on the side wall of the clamping arm.

[0009] Preferably, the tensioning assembly includes a mounting hole formed on the side wall of the clamping arm, a first groove block communicating with the mounting hole is fixed on the back of the clamping arm, a tensioning block is slidably connected to the inside of the first groove block and the mounting hole, a slot is formed at the end of the tensioning block, and a tensioning shaft is rotatably connected inside the slot, and a tensioning spring is fixed between the tensioning block and the first groove block.

[0010] Preferably, the side wall of the U-shaped pressure holding block is fixed with two sets of connecting blocks, and the two connecting blocks in the same set are rotatably connected by a first guide shaft. The outer side wall of the support sleeve and the side wall of the clamping arm are fixed with two sets of corner blocks, and the two corner blocks in the same set are rotatably connected by a second guide shaft. The end of the steel wire away from the winding wheel passes around the second guide shaft and the first guide shaft on the same side in sequence and is connected to the slider.

[0011] Preferably, the reset assembly includes a second groove block fixed to the side wall of the U-shaped pressure block, and a reset spring is fixed to the inner side wall of the second groove block. The end of the reset spring away from the second groove block slides through the wall of the strip hole and is fixedly connected to the side wall of the slider.

[0012] Preferably, a torque sensor is fixed to the side wall of the winding box, and the detection end of the torque sensor is connected to the rotating shaft drive. The torque sensor is electrically connected to the control end of the robotic arm body, and the control end of the robotic arm body controls the operation of the lead screw drive assembly according to the electrical signal fed back by the torque sensor.

[0013] Compared with existing technologies, the advantages of a robot for welding automotive parts are: 1. Through the cooperation of the robotic arm body, mounting plate, clamping arm, electrode welding head and drive mechanism, resistance welding of automotive stamped parts can be performed. Through the cooperation of the support sleeve, U-shaped pressure holding block and square spring, pre-pressure can be applied around the weld point during resistance welding. After welding, it can replace the electrode welding head to hold pressure at the weld point. This not only reduces the impact of high springback of stamped parts such as aluminum alloys on the weld point, but also reduces the end face collapse of the electrode welding head caused by continuous pressure holding, which helps to extend the service life of the electrode welding head.

[0014] 2. By using the extrusion exhaust unit, the air in the welding area can be expelled before resistance welding, avoiding the formation of a closed air chamber between the mating surfaces, eliminating porosity and spatter caused by the thermal expansion of air during welding, and improving the joint forming quality.

[0015] 3. By using the torque sensor, the pressure caused by the springback force of the workpiece can be used to help determine the required holding time after welding based on the pressure of the extrusion exhaust unit. This ensures that the holding time after welding is sufficient and further reduces the impact of the high springback of the stamped parts on the pullback of the weld. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of a robot for welding automotive parts provided by the present invention; Figure 2 This is a side view of the gripper arm of a robot for welding automotive parts provided by the present invention. Figure 3 This is a top view schematic diagram of the gripper arm of a robot for welding automotive parts provided by the present invention; Figure 4 This is a schematic diagram of the internal structure of the support sleeve of a robot for welding automotive parts provided by the present invention; Figure 5 This is a schematic diagram of the internal structure of the winding box of a robot for welding automotive parts provided by the present invention; Figure 6 This is a schematic diagram of the tensioning assembly of a robot for welding automotive parts provided by the present invention; Figure 7 This is a schematic diagram of the connection structure between the second slot block and the slider of a robot for welding automotive parts provided by the present invention.

[0017] In the diagram: 1. Main body of the robotic arm; 2. Mounting plate; 3. Clamping arm; 4. Electrode welding head; 5. Drive mechanism; 51. Box body; 52. Screw drive assembly; 6. Support sleeve; 7. U-shaped pressure holding block; 8. Square spring; 9. Extrusion exhaust unit; 91. Pressure shaft; 92. Slider; 93. Strip hole; 10. Rewinding mechanism; 101. Rewind box; 102. Rotary shaft; 103. Rewinding wheel; 104. Steel wire; 105. Motor; 11. Reset assembly; 111. Second slot block; 112. Reset spring; 12. Tensioning assembly; 121. Mounting hole; 122. First slot block; 123. Tensioning block; 124. Tensioning shaft; 125. Tensioning spring; 13. Connecting block; 14. First guide shaft; 15. Corner block; 16. Second guide shaft; 17. Torque sensor. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] like Figures 1-7 As shown, a robot for welding automotive parts includes a robotic arm body 1 and a mounting plate 2 installed at the end of the robotic arm body 1. It also includes two symmetrically arranged clamping arms 3, both positioned below the mounting plate 2. Removable electrode welding heads 4 are mounted on the opposite sidewalls of the two clamping arms 3. The mounting plate 2 is equipped with a drive mechanism 5 for moving the two clamping arms 3. The drive mechanism 5 includes a housing 51 detachably mounted at the bottom of the mounting plate 2. Both clamping arms 3 are slidably connected to the inner wall of the housing 51. A lead screw drive assembly 52 is installed on the sidewall of the housing 51, and the lead screw drive assembly 52 drives the two clamping arms 3 to move along the inside of the housing 51. The lead screw drive assembly 52 is electrically connected to the control end of the robotic arm body 1. The lead screw drive assembly 52 includes components such as a lead screw, a lead screw nut, a bearing, a drive block, and a servo motor.

[0020] Two support sleeves 6 are fixed to the opposite side walls of two clamping arms 3 respectively. U-shaped pressure holding blocks 7 are slidably connected to the inner walls of the two support sleeves 6. A square spring 8 is fixed between the U-shaped pressure holding block 7 and the side wall of the clamping arm 3. The electrode welding head 4 is set inside the U-shaped pressure holding block 7. The extrusion exhaust unit 9 is set inside the U-shaped pressure holding block 7. The extrusion exhaust unit 9 is used to expel the air in the welding area. The extrusion exhaust unit 9 includes a pressure shaft 91 set inside the U-shaped pressure holding block 7. Both ends of the pressure shaft 91 are rotatably connected to sliders 92. Both side walls of the U-shaped pressure holding block 7 are provided with strip holes 93 that match the sliders 92. The sliders 92 are slidably set inside the strip holes 93. The clamping arm 3 is equipped with a pulling mechanism 10 that drives the sliders 92 to move. The shaft wall of the pressure shaft 91 is flush with the end of the U-shaped pressure holding block 7.

[0021] The take-up mechanism 10 includes a take-up box 101 fixed to the side wall of the gripper arm 3. A rotating shaft 102 is rotatably connected inside the take-up box 101, and two take-up wheels 103 are fixedly sleeved on the shaft wall of the rotating shaft 102. Steel wire 104 is wound around the take-up wheels 103. A motor 105 is fixed to the side wall of the take-up box 101. The end of the steel wire 104 away from the take-up wheels 103 slides through the wall of the strip-shaped hole 93 and is fixedly connected to the side wall of the slider 92. The motor 105 is electrically connected to the control end of the robotic arm body 1. A tensioning assembly 12 corresponding to the steel wire 104 is installed on the side wall of the gripper arm 3. The tensioning assembly 12 includes mounting holes 121 opened in the side wall of the gripper arm 3. The back of arm 3 is fixed with a first groove block 122 that communicates with the mounting hole 121. The first groove block 122 and the mounting hole 121 are slidably connected to a tension block 123. The end of the tension block 123 is provided with a slot, and the tension shaft 124 is rotatably connected inside the slot. A tension spring 125 is fixed between the tension block 123 and the first groove block 122. When the support sleeve 6 and the U-shaped pressure block 7 move relative to each other, the relative distance between the winding wheel 103 and the slider 92 changes. At this time, the tension spring 125 and the tension block 123 drive the tension shaft 124 to move, which can tension the steel wire 104 and ensure that the steel wire 104 maintains a suitable tension.

[0022] Two sets of connecting blocks 13 are fixed to the side wall of the U-shaped pressure block 7, and a first guide shaft 14 is rotatably connected between the two connecting blocks 13 in the same set. Two sets of corner blocks 15 are fixed between the outer side wall of the support sleeve 6 and the side wall of the clamping arm 3, and a second guide shaft 16 is rotatably connected between the two corner blocks 15 in the same set. The end of the steel wire 104 away from the winding wheel 103 passes through the second guide shaft 16 and the first guide shaft 14 on the same side in sequence and is connected to the slider 92. The steel wire 104 can be guided by the first guide shaft 14 and the second guide shaft 16 to ensure the stability of the steel wire 104.

[0023] The U-shaped pressure holding block 7 is equipped with a reset assembly 11 connected to the slider 92. The reset assembly 11 includes a second groove block 111 fixed to the side wall of the U-shaped pressure holding block 7. A reset spring 112 is fixed to the inner side wall of the second groove block 111. The end of the reset spring 112 away from the second groove block 111 slides through the hole wall of the strip hole 93 and is fixedly connected to the side wall of the slider 92. The reset spring 112 can facilitate the slider 92 to reset the pressure shaft 91.

[0024] A torque sensor 17 is fixed to the side wall of the winding box 101, and the detection end of the torque sensor 17 is connected to the rotating shaft 102 for transmission. The torque sensor 17 is electrically connected to the control end of the robotic arm body 1, and the control end of the robotic arm body 1 controls the operation of the lead screw drive assembly 52 according to the electrical signal fed back by the torque sensor 17. The torque sensor 17 can convert the torque into an electrical signal and feed it back to the control end of the robotic arm body 1.

[0025] The operating principle of this invention is explained as follows: The stamped part to be welded is clamped and fixed on the tooling. The control end of the robotic arm body 1 controls the robotic arm body 1 to work according to the program. The robotic arm body 1 drives the two electrode welding heads 4 to move to both sides of the area to be welded through the mounting plate 2 and the clamping arms 3. Subsequently, the control end of the robotic arm body 1 controls the lead screw drive assembly 52 to drive the two clamping arms 3 to move towards each other along the inside of the box 51 (the lead screw drive assembly 52 includes components such as lead screw, lead screw nut, bearing, drive block, and servo motor). At this time, the two clamping arms 3 will drive the two U-shaped pressure holding blocks 7 to move towards each other through the support sleeve 6. When the U-shaped pressure holding blocks 7 and the pressure shaft 91 abut against the side wall of the workpiece welding area, the U-shaped... The pressure holding block 7 and the pressure shaft 91 stop moving, while the clamping arm 3 drives the support sleeve 6 to continue moving. At this time, the clamping arm 3 applies pressure to the U-shaped pressure holding block 7 through the square spring 8. The U-shaped pressure holding block 7 then applies pressure to the welding point area, thereby completing the pre-compression of the welding point area. The electrode welding head 4 does not need to participate in the pre-compression directly, avoiding premature stress on the electrode and causing wear. As the electrode welding head 4 continues to work, its temperature rises continuously and its material hardness decreases. It is extremely easy to be deformed and collapse under pressure at high temperatures. Therefore, by using the U-shaped pressure holding block 7 to pre-compress the welding point area, the pressure load on the electrode welding head 4 can be greatly reduced, protecting the electrode welding head 4 from being squeezed and deformed at high temperatures, which helps to extend the service life of the electrode welding head 4. Secondly, as the support sleeve 6 moves, when the relative displacement between the support sleeve 6 and the U-shaped pressure block 7 reaches 4cm, the control end of the robotic arm body 1 controls the screw drive assembly 52 to pause operation according to the program, and then starts the motor 105. The motor 105 drives the two winding wheels 103 to rotate through the rotating shaft 102. The winding wheels 103 then wind the steel wire 104, thereby causing the steel wire 104 to pull the slider 92 to move. The slider 92 then drives the pressure shaft 91 to move synchronously. The pressure shaft 91 moves from one side to the other along the welding area inside the U-shaped pressure block 7. Since the three sides of the U-shaped pressure block 7 simultaneously form a U-shaped pressure area on the welding area, the pressure from the three sides of the U-shaped pressure block 7 can prevent air from flowing from the outer area of ​​the weld joint to the weld joint. Under the squeezing action of the moving pressure shaft 91, the air in the inner area of ​​the weld joint can be forced out of the U-shaped pressure block. The inner side of block 7 is pressed towards the opening of U-shaped pressure block 7, and the final pressure shaft 91 moves to the opening area of ​​U-shaped pressure block 7, so as to form four-sided pressure with U-shaped pressure block 7, preventing air from flowing back into the welding area from the outside of the welding area, and thus squeezing out the air inside the welding area in advance. After the motor 105 finishes working according to the program, the control end of the robotic arm body 1 controls the screw drive assembly 52 to resume working and continue to drive the clamping arm 3 to move the electrode welding head 4, so that the electrode welding head 4 abuts against the side wall of the workpiece welding area. Then the electrode welding head 4 can be controlled to work to complete the welding work of the welding area. Since the air inside the welding area has been squeezed out in advance, the formation of a closed air chamber on the workpiece contact surface can be avoided as much as possible, eliminating the porosity and spatter caused by the thermal expansion of air during welding, and improving the joint forming quality. After welding is completed, the control end of the main body 1 of the robotic arm controls the lead screw drive assembly 52 to drive the clamping arm 3 to move the electrode welding head 4 back by 1cm, so that the electrode welding head 4 is removed from the welding area. The square spring 8 and the U-shaped pressure holding block 7 continue to apply pressure to the welding area to prevent the weld point, which is in a hot and low-strength state after welding, from developing micro-cracks, shrinkage cavities or weld point pull-out under the action of workpiece rebound pull. At the same time, it avoids the weld point from sinking and deforming when it cools and shrinks, further ensuring the weld point forming quality and structural strength, making up for the defect of the weld point losing its constraint after the electrode welding head 4 is removed. Moreover, there is no need for the electrode welding head 4 to hold pressure on the welding area, which can minimize the problems of excessive end face collapse and wear of the electrode welding head 4 due to high temperature and high pressure, and reduce the possibility of defects in the weld point due to workpiece pull-back. When the motor 105 drives the rotating shaft 102 to wind the winding wheel 103 around the steel wire 104, if the workpiece is flat and without springback stress, the pressure shaft 91 only bears the pressure applied to the workpiece by the U-shaped pressure holding block 7. If the workpiece has springback gaps, the pressure shaft 91 will also be subjected to additional loads from the reverse push of the workpiece. Therefore, the friction force of the pressure shaft 91 is greater when it moves. At this time, the load torque detected by the torque sensor 17 will increase significantly. After welding is completed, the control end of the robotic arm body 1 will adaptively adjust the holding time according to the torque magnitude. For areas with high springback, the holding time is extended to further ensure the cooling and shaping quality of the weld joint. For example, when the torque detected by the torque sensor 17 is less than 1.2 N·m, it is determined that the workpiece springback is small, and the control end performs a standard holding time of 1 second. When the detected torque is ≥1.2 N·m, it is determined that the springback is large, and the holding time is automatically extended to 2 seconds. For every 0.5 N·m increase in torque, the holding time is increased by 1 second. The pressure is released only after the weld joint is completely solidified, so as to minimize the damage of the workpiece springback to the weld joint and further reduce the possibility of defective weld joints. After the pressure holding period ends, the control end of the robotic arm body 1 controls the lead screw drive assembly 52 to drive the clamping arm 3 to reset. At this time, the U-shaped pressure holding block 7 is disengaged from the workpiece, and the control end of the robotic arm body 1 controls the motor 105 to reverse, releasing the steel wire 104. Under the action of the square spring 8 and the reset spring 112, both the U-shaped pressure holding block 7 and the slider 92 will reset. At the same time, the control end of the robotic arm body 1 controls the robotic arm body 1 to perform welding of the next weld point according to the program.

[0026] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A robot for welding automotive parts, comprising a robotic arm body (1) and a mounting plate (2) installed at the end of the robotic arm body (1), characterized in that, Also includes: Two symmetrically arranged clamping arms (3) are both located below the mounting plate (2). Removable electrode welding heads (4) are installed on the opposite sidewalls of the two clamping arms (3). The mounting plate (2) is equipped with a driving mechanism (5) for driving the two clamping arms (3) to move. Two support sleeves (6) are fixed to the opposite side walls of the two clamping arms (3), and the inner walls of the two support sleeves (6) are slidably connected with U-shaped pressure blocks (7), and a square spring (8) is fixed between the U-shaped pressure blocks (7) and the side walls of the clamping arms (3). The electrode welding head (4) is set inside the U-shaped pressure blocks (7). An extrusion exhaust unit (9) is disposed inside the U-shaped pressure block (7) and is used to expel air from the welding area by extrusion.

2. The robot for welding automotive parts according to claim 1, characterized in that, The drive mechanism (5) includes a box (51) detachably mounted on the bottom of the mounting plate (2). The two clamping arms (3) are slidably connected to the inner wall of the box (51). A screw drive assembly (52) is installed on the side wall of the box (51), and the screw drive assembly (52) drives the two clamping arms (3) to move along the inside of the box (51). The screw drive assembly (52) is electrically connected to the control end of the robotic arm body (1).

3. The robot for welding automotive parts according to claim 2, characterized in that, The extrusion exhaust unit (9) includes a pressure shaft (91) disposed inside the U-shaped pressure holding block (7). Both ends of the pressure shaft (91) are rotatably connected to sliders (92). Both side walls of the U-shaped pressure holding block (7) are provided with strip holes (93) that match the sliders (92). The sliders (92) are slidably disposed inside the strip holes (93). The clamping arm (3) is equipped with a pull-up mechanism (10) that drives the sliders (92) to move. The U-shaped pressure holding block (7) is equipped with a reset assembly (11) connected to the sliders (92).

4. The robot for welding automotive parts according to claim 3, characterized in that, The winding mechanism (10) includes a winding box (101) fixed to the side wall of the clamping arm (3). The winding box (101) is rotatably connected to a rotating shaft (102), and two winding wheels (103) are fixedly sleeved on the shaft wall of the rotating shaft (102). The winding wheels (103) wind and wind up a steel wire (104). A motor (105) is fixed to the side wall of the winding box (101). The end of the steel wire (104) away from the winding wheel (103) slides through the hole wall of the strip hole (93) and is fixedly connected to the side wall of the slider (92). The motor (105) is electrically connected to the control end of the robotic arm body (1). A tensioning component (12) corresponding to the steel wire (104) is installed on the side wall of the clamping arm (3).

5. The robot for welding automotive parts according to claim 4, characterized in that, The tensioning assembly (12) includes a mounting hole (121) on the side wall of the clamping arm (3). A first groove block (122) communicating with the mounting hole (121) is fixed on the back of the clamping arm (3). A tensioning block (123) is slidably connected inside the first groove block (122) and the mounting hole (121). A slot is provided at the end of the tensioning block (123), and a tensioning shaft (124) is rotatably connected inside the slot. A tensioning spring (125) is fixed between the tensioning block (123) and the first groove block (122).

6. The robot for welding automotive parts according to claim 4, characterized in that, The side wall of the U-shaped pressure block (7) is fixed with two sets of connecting blocks (13), and the two connecting blocks (13) in the same set are rotatably connected with a first guide shaft (14). The outer side wall of the support sleeve (6) and the side wall of the clamping arm (3) are fixed with two sets of corner blocks (15), and the two corner blocks (15) in the same set are rotatably connected with a second guide shaft (16). The end of the steel wire (104) away from the winding wheel (103) passes around the second guide shaft (16) and the first guide shaft (14) on the same side in sequence and connects to the slider (92).

7. The robot for welding automotive parts according to claim 3, characterized in that, The reset assembly (11) includes a second slot block (111) fixed to the side wall of the U-shaped pressure block (7). A reset spring (112) is fixed to the inner side wall of the second slot block (111). The end of the reset spring (112) away from the second slot block (111) slides through the hole wall of the strip hole (93) and is fixedly connected to the side wall of the slider (92).

8. The robot for welding automotive parts according to claim 4, characterized in that, A torque sensor (17) is fixed to the side wall of the winding box (101), and the detection end of the torque sensor (17) is connected to the rotating shaft (102) for transmission. The torque sensor (17) is electrically connected to the control end of the robotic arm body (1), and the control end of the robotic arm body (1) controls the operation of the lead screw drive assembly (52) according to the electrical signal fed back by the torque sensor (17).

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