A tetrahedron tumbling robot and a method for optimizing motion joint parameters thereof

Abstract

The present invention relates to a tetrahedron tumbling robot and a method for optimizing its motion joint parameters, wherein the robot realizes tumbling motion by the combined swinging of its support arms, the motion steps are simple and each joint can be independently controlled, which simplifies the overall structure of the robot and reduces the control difficulty; by determining the characteristic parameters of the tetrahedron tumbling robot, the tumbling shape of the tetrahedron tumbling robot is screened out in combination with the tumbling conditions; the optimal target value of the swing joint is determined by the relationship between the robot's shape and the time required for tumbling at a specific joint motion speed; and a method for changing the angle of the robot's rotating joint is provided. Compared with the prior art, the present invention solves the shortcomings of the tetrahedron tumbling robot having many motion steps and a time-consuming motion process, so that the corresponding tetrahedron tumbling robot takes the shortest time to move under the joint parameters, thereby improving the robot's motion efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of tetrahedron robots, and in particular to a tetrahedron tumbling robot and a method for optimizing motion joint parameters thereof. Background Art

[0002] In recent years, mobile robots used for land environment exploration have become a hot topic in robot research. Traditional mobile robots cannot cope with complex ground environments, which poses new challenges to the environmental adaptability of mobile robots. Tumbling robots perform tumbling motion by changing their own shape, overcoming the problem that traditional mobile robots lose their ability to move after overturning in unknown environments. Research on tumbling robot motion is of great significance to the development of mobile robots.

[0003] Chinese patent application CN101664926A proposes a tetrahedron tumbling robot with a parallel mechanism, which is composed of six telescopic arms and four node plates. It has a strong deformation ability and can realize the tumbling of the robot itself through the telescopic arms, but the sizes of the telescopic arms are interrelated during the deformation movement, and the control accuracy required for the change of the length of the telescopic arms is high and the control process is complicated. Chinese patent application CN104118488A proposes an autonomously movable tumbling robot, which is connected to a central connecting block by four telescopic support arms, and the other ends of the support arms correspond to the four vertices of a regular tetrahedron. It can use omnidirectional wheels to realize movement in any direction on a plane, and can also move its own center of gravity by telescoping and swinging the support arms to perform tumbling. However, during the tumbling action, the support arms need to be swung and telescopically deformed at the same time, which makes the structure of the robot support arms complex and also causes the complexity of motion control.

[0004] In summary, although scholars have conducted many studies on tetrahedron tumbling robots, this type of tumbling robot still has the disadvantages of many tumbling steps and time-consuming movement process. Summary of the invention

[0005] The purpose of the present invention is to provide a tetrahedron tumbling robot and a method for optimizing the motion joint parameters thereof in order to overcome the defects of the above-mentioned prior art. In the present invention, a tetrahedron tumbling robot is designed, which realizes tumbling motion by the combined swing of its support arms. The action steps are simple and each joint can be independently controlled, which simplifies the overall structure of the robot and reduces the control difficulty. During the robot movement process, the proposed joint parameter optimization method enables the robot to perform the shortest tumbling motion under the parameters, thereby improving the robot's motion efficiency.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A tetrahedron tumbling robot, characterized in that it comprises a support arm A, a support arm B, a support arm C, a support arm D and a central block;

[0008] The support arm A comprises a rotating joint, a swinging joint and a control circuit board, wherein the rotating joint and the swinging joint are respectively provided with motors, and the motors are used to control the angles of the rotating joint and the swinging joint;

[0009] The support arm B, support arm C and support arm D have the same structure as support arm A;

[0010] The rotating joints on the support arm A, the support arm B, the support arm C and the support arm D are respectively connected to the central block;

[0011] The control circuit board controls the rotation of the rotary joints and the swing joints on each support arm to realize the tumbling motion of the robot.

[0012] Furthermore, a rotating shaft is provided on the rotating joint;

[0013] The rotary joint is connected to the swing joint through a thrust bearing, a top screw is provided to fix the circumferential rotation angle of the swing joint relative to the rotating shaft of the rotary joint, and a double nut is used to fix the axial position of the swing joint relative to the rotary joint.

[0014] Furthermore, the support arm A also includes a support arm structure plate and a circuit board bracket;

[0015] The circuit board bracket is arranged on the support arm structure plate; the control circuit board is arranged on the circuit board bracket; the control circuit board is used to receive the rotation angle signal transmitted by the motors in the rotating joint and the swinging joint, and to control the angles of the motors in the two joints;

[0016] The support arm structure plate is installed on the rotating shaft of the swing joint.

[0017] Furthermore, in the rotary joint, a joint cover is provided to mount the motor in the joint seat, and transmit the power to the rotating shaft through the worm gear structure;

[0018] Bolt a, bolt b, nut b, bolt c and nut c are provided to fix the joint cover and the joint seat;

[0019] A zero-position baffle is provided on the rotating shaft. When the rotating shaft rotates to a certain position, the zero-position baffle triggers the zero-position switch on the rotating joint;

[0020] The bolt is installed in the threaded hole on the front side of the joint seat. After being screwed in, a part of the threaded section enters the hole of the worm, which is used to assist in supporting the worm and reduce the deformation caused by the radial force of the worm wheel on the worm.

[0021] Furthermore, the control circuit board includes a reset button 1, a reset button 2, a wireless communication module, a power module, a microcontroller and a motor drive module, and the control circuit board is connected to the zero position switch and the motor in the rotating joint and the swing joint in the same support arm;

[0022] The microcontroller is connected to an external host computer;

[0023] The power supply module is used to supply power to the other modules, and the wireless communication module is used to control the information exchange between the microcontroller in the support arm and the host computer;

[0024] The microcontroller is used to send corresponding control instructions to the motor drive module according to the host computer instructions; the motor drive module is used to control the motors in the rotating joint and the swinging joint respectively according to the control instructions;

[0025] The reset button is used to calibrate the joints after the robot is powered on for the first time.

[0026] Furthermore, the swing joint and the rotary joint differ only in the subsequent connection structure of the output shaft. In the swing joint, the support arm structure plate replaces the positioning sleeve and the zero position baffle in the rotary joint.

[0027] After connecting the components as above, they need to be adjusted, including the following steps:

[0028] T1. After the robot is powered on, press the reset button in each support arm, and the joints of the robot move to the zero position.

[0029] T2. Place the robot on the ground so that support arms A, B and C are in contact with the ground, and support arm D is pointing vertically upward.

[0030] T3. Adjust the circumferential position of the swing joints on support arm A, support arm B, and support arm C relative to the rotation axis in the rotation joint so that the swing planes of support arm A, support arm B, and support arm C are perpendicular to the ground.

[0031] T4. Adjust the circumferential position of the swing joint on the support arm D relative to the rotation axis in the rotary joint so that the swing plane of the support arm D is perpendicular to the BC line and the swing direction is toward the BC line.

[0032] Through the above connection and adjustment, a tetrahedron tumbling robot corresponding to the method of the present invention is formed. At this time, the straight lines where the robot's support arms A, B, C, and D are located converge at the center block, and the robot is defined to be in an initial state.

[0033] The motion method of the tetrahedron tumbling robot corresponding to the method of the present invention comprises the following steps:

[0034] Y1, the swing joints on support arm A and support arm D rotate through angle θ sA With θ sD , the robot rolls along the line BC.

[0035] Y2. After the robot completes the roll, support arm A and support arm D return to their respective joint zero positions. At this time, the straight lines where the four support arms of the robot are located converge again at the center block.

[0036] Y3, control the rotation joints of support arm B, support arm C and support arm A to rotate by θ rB ,θ rC With θ rA , the robot completes a cycle of tumbling motion and defines the state at this time as the initial state of the next tumbling cycle.

[0037] The above steps complete one cycle of the tumbling motion of the tetrahedron tumbling robot described in the present invention. According to the selection of the subsequent motion direction, the support arm is mapped to the initial state in sequence and the above motion process can be repeated without modification.

[0038] Specifically, if the subsequent roll is around the CD line, the support arm BDCA is remapped to the support arm ABCD; if the subsequent roll is around the BD line, the support arm CBDA is remapped to the support arm ABCD; if the subsequent roll is around the BC line, the support arm DCBA is mapped to the support arm ABCD.

[0039] After multiple tumbling cycles, the robot can complete directional movement on the ground.

[0040] A method for optimizing motion joint parameters of a tetrahedron tumbling robot, applied to the tetrahedron tumbling robot as described above, comprises the following steps:

[0041] Determine the characteristic parameters of the tetrahedron tumbling robot;

[0042] According to the robot's rolling condition f, the shape that can make the robot roll is selected (θ sA ,θ sD ) Among them, θ sA is the swing joint angle of support arm A, θ sD is the swing joint angle of the support arm D;

[0043] like If it is an empty set, the characteristic parameters of the tetrahedron tumbling robot are readjusted;

[0044] like If not empty, calculate The middle element (θ sA ,θ sD) at a specific swing joint angular velocity Next, the time t taken by the tetrahedron tumbling robot to complete the tumbling;

[0045] According to the minimum value of the rolling time t, the angular velocity of the tetrahedron rolling robot at a specific swing joint is determined. The corresponding θ sA With θ sD ;

[0046] Determine the angle θ of the rotation joint of support arm B rB and the angle θ of the rotation joint of the support arm C rC , during the robot's rolling motion, θ rB With θ rC The angle is updated based on the base value of its own joint;

[0047] The angle θ of the rotation joint of support arm A rA ;

[0048] Among them, θ rB The relationship between the new value of and its old value is:

[0049] θ rB_new =mod(θ rB_old +120°,360°)

[0050] θ rC The relationship between the new value of and its old value is:

[0051] θ rC_new =mod(θ rC_old -120°,360°)

[0052] Determine the angle θ of the rotation joint of support arm A rA , during the robot's rolling motion, θ rA The angle is updated based on the base value of its own joint, and θ is determined according to the subsequent rolling axis of the tetrahedron rolling robot. rA .

[0053] Furthermore, the characteristic parameters of the robot include: the length r from the center of the robot to the rotation axis of each support arm swing joint, the length l from the axis of each support arm swing joint to the end, the mass m contained in the sphere with a radius of r from the center of the robot center , the mass m contained in each support arm outside the radius r from the center of the robot leg , each support arm swings the joint axis to m leg The distance l from the center of mass c And the maximum angle θ of the robot's swing joint max .

[0054] Furthermore, the rolling condition f of the robot is determined by the spatial position of the robot center block, the spatial position of the center of mass of each support arm of the robot, m center , and m leg The formula for the rollover condition f is determined jointly by:

[0055]

[0056] Among them, x center is the distance between the projection of the spatial position of the robot center block on the ground and the line connecting the rolling axis BC, x ic It is the distance between the projection of the center of mass of the support arm on the ground and the line BC.

[0057] Further, The middle element (θ sA ,θ sD ) at a specific swing joint angular velocity Under this condition, the calculation formula of the time t taken by the tetrahedron tumbling robot to complete the tumbling is:

[0058]

[0059] Among them, θ flip is the total angle of rotation of the robot around the rolling axis BC during the rolling process, θ flip =arctan(y D / x D ), y D The end point D of the tetrahedron tumbling robot support arm D is (θ sA ,θ sD ) shape from the ground, x D is the distance from the projection of point D of the tetrahedron tumbling robot on the ground to the tumbling axis BC; ω is the angular velocity of the swing joint of the tetrahedron tumbling robot Under the condition of moving to (θ sA ,θ sD ) when the robot's overall mass center is around the rolling axis BC axis; m equ is the total mass of the tetrahedron tumbling robot; g is the acceleration due to gravity; l equ is the distance between the center of mass of the tetrahedron tumbling robot and the tumbling axis BC at this time; J is the moment of inertia of the tetrahedron tumbling robot around the tumbling axis BC at this time.

[0060] Furthermore, the angle θ of the rotation joint of the support arm A is rA The relationship between the changing rule of and the subsequent rolling axis selected by the tetrahedron rolling robot is as follows:

[0061] When CD is used as the next rolling axis, θ rA_new =mod(θrA_old -120°, 360°); when BD is used as the next rolling axis, θ rA_new =mod(θ rA_old +120°,360°); when BC is used as the next rolling axis, θ rA_new =θ rA_old .

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. The tetrahedron tumbling machine proposed in the present invention realizes tumbling motion by the combined swinging of its support arms. The action steps are simple and each joint can be independently controlled. Only rotating joints are used to realize tumbling motion, which greatly simplifies the mechanical structure and motion steps of the tetrahedron robot. At the same time, it simplifies the overall structure of the robot and reduces the control difficulty. Compared with the robot in the prior art, the structure is relatively simple and easy to perform motion control.

[0064] 2. During the movement of the corresponding tetrahedron tumbling robot, the joint parameters determined by the present invention enable the robot to take the shortest time during the tumbling movement, thereby improving the movement efficiency of the robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is the overall structure diagram of the tetrahedron tumbling robot corresponding to the present invention.

[0066] Figure 2 This is an exploded view of the tetrahedron tumbling robot corresponding to the present invention.

[0067] Figure 3 This is a structural diagram of a supporting arm in a tetrahedron tumbling robot corresponding to the present invention.

[0068] Figure 4 The figure is an exploded view of a supporting arm of the tetrahedron tumbling robot corresponding to the present invention.

[0069] Figure 5 This is a structural diagram of the robot joints in the tetrahedron tumbling robot corresponding to the present invention.

[0070] Figure 6 This is an exploded view of the robot joints in the tetrahedron tumbling robot corresponding to the present invention.

[0071] Figure 7 This is a functional block diagram of a control circuit board in a tetrahedron tumbling robot corresponding to the present invention.

[0072] Figure 8 The figure is a schematic diagram of the tumbling motion process of the tetrahedron tumbling robot corresponding to the present invention.

[0073] Fig. 9This is a flow chart of a method for optimizing motion joint parameters of a tetrahedron tumbling robot proposed in the present invention.

[0074] Fig.10 This is a definition diagram of the characteristic parameters of the tetrahedron tumbling robot corresponding to the present invention.

[0075] The markings in the figure are as follows: 1000-support arm A, 2000-support arm B, 3000-support arm C, 4000-support arm D, 5000-center block; 1100-rotation joint, 1200-thrust bearing, 1300-swing joint, 1400-top screw, 1500-double nut, 1600-support arm structure plate, 1700-circuit board bracket, 1800-control circuit board; 1101-joint seat, 11 02-bolt a, 1103A-bolt b, 1103B-nut b, 1104-zero position switch, 1105-joint cover, 1106A-bolt c, 1106B-nut c, 1107-motor, 1108A-worm, 1108B-worm wheel, 1109A-ball bearing a, 1109B-ball bearing b, 1110-rotating shaft, 1111-bolt d, 1112-positioning spacer, 1113-zero position baffle. DETAILED DESCRIPTION

[0076] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0077] The tetrahedron tumbling robot of the present invention has a different movement mode from the existing tetrahedron tumbling robots. The parallel tetrahedron tumbling robot proposed in Chinese patent application CN101664926A is composed of six telescopic arms and four node plates, and realizes its own tumbling through the telescopic arms. The autonomously movable tumbling robot proposed in Chinese patent application CN104118488A needs to use the support arm telescopic movement to complete the movement during the tumbling process. The tetrahedron tumbling robot and its movement method described in the present invention only use rotating joints to realize the tumbling movement, which greatly simplifies the mechanical structure and movement steps of the tetrahedron robot.

[0078] The present invention will be further described in detail below with reference to the accompanying drawings.

[0079] See also Figure 1 , Figure 2 As shown, a tetrahedron tumbling robot involved in the present invention is composed of a support arm A1000, a support arm B2000, a support arm C3000, a support arm D4000 and a central block 5000.

[0080] Specifically, the support arm A1000, support arm B2000, support arm C3000 and support arm D4000 have the same structure. The rotation joints 1100 in the support arm A1000, support arm B2000, support arm C3000 and support arm D4000 are respectively connected and fixed to the corresponding holes on the central block 5000 using bolts.

[0081] See also Figure 3 , Figure 4 As shown, the support arm A1000 is mainly composed of a rotating joint 1100 , a swing joint 1300 , a support arm structural plate 1600 and a control circuit board 1800 .

[0082] Specifically, the rotating joint 1100 is connected to the swing joint 1300 through the thrust bearing 1200. After adjusting the relative angle between the two joints, the top screw 1400 is used to fix the circumferential rotation angle of the swing joint 1300 relative to the rotating shaft 1110 of the rotating joint 1100, and the axial position of the swing joint 1300 relative to the rotating joint 1100 is fixed by the double nut 1500.

[0083] Specifically, the support arm structure plate 1600 is mounted on the rotating shaft 1110 of the swing joint 1300 , and the circumferential angles of the two are fixed by the shapes of the rotating shaft 1110 and the holes on the support arm structure plate 1600 .

[0084] Specifically, the control circuit board 1800 is installed on the support arm structure board 1600 through the circuit board bracket 1700. It is used to receive the rotation angle signal transmitted by the motor 1107 in the rotating joint 1100 and the swing joint 1300, and perform angle control on the motor 1107 in the two joints.

[0085] See also Figure 5 , Figure 6 As shown, in the rotary joint 1100 , the motor 1107 is installed in the joint seat 1101 using a joint cover 1105 , and the power is transmitted to the rotating shaft 1110 through a worm gear structure.

[0086] Specifically, bolt a1102, bolt b1103A, nut b1103B, bolt c1106A, and nut c1106B clamp the joint cover 1105 and the joint seat 1101. When the motor 1107 rotates, it drives the worm 1108A, and then drives the worm wheel 1108B to transmit the rotational motion to the rotating shaft 1110. The rotating shaft 1110 is equipped with a zero position baffle 1113. When the rotating shaft 1110 rotates to a certain position, the zero position baffle 1113 triggers the zero position switch 1104, and the motor 1107 stops rotating at this time, and this position is set as the zero position of the motor 1107.

[0087] Bolt d1111 is installed in the threaded hole on the front side of joint seat 1101, and a part of the threaded section will enter the hole of worm 1108A after being screwed in. This plays a role of auxiliary support of worm 1108A and reduces the deformation caused by the radial force of worm wheel 1108B on worm 1108A.

[0088] In the swing joint 1300, the main structure is the same as that of the rotary joint 1100. The difference is that in the swing joint 1200, the positioning sleeve 1112 and the zero-position baffle 1113 on the rotating shaft 1110 are replaced by the support arm structure plate 1600. The support arm structure plate 1600 realizes the function of the zero-position baffle 1113 through the raised plane shape, triggering the zero-position switch 1104 in the swing joint 1300.

[0089] See also Figure 7 As shown, the control circuit board 1800 is mainly composed of a reset button 1, a reset button 2, a wireless communication module, a power module, a microcontroller and a motor drive module, and is connected to the zero position switch 1104 and the motor 1107 in the rotating joint 1100 and the swing joint 1300 in the same support arm.

[0090] Specifically, in the control circuit board, the power module supplies power to the other modules, and the wireless communication module is responsible for the information exchange between the microcontroller in the support arm and the host computer. After receiving the host computer command, the microcontroller returns a response signal and sends corresponding control instructions to the motor drive module according to the set program. The motor drive module controls the two motors 1107 in the rotating joint 1100 and the swing joint 1300 respectively according to the instruction. During the operation of the motor, the Hall signal of the motor is fed back to the microcontroller, thereby forming a closed-loop control of the angle of the motor 1107.

[0091] When the motor 1107 encounters the joint zero position during movement, it triggers the zero position switch 1104 in the joint. After the zero position switch 1104 is triggered, the signal is fed back to the microcontroller to stop the motor movement and calibrate the angle signal of the corresponding motor in the microcontroller to 0.

[0092] The reset button is used to calibrate the joints after the robot is powered on for the first time, and drives the motor 1107 to rotate until the zero position switch 1104 is triggered, so as to return the corresponding joint to the set zero position.

[0093] After connecting the components as described above, they need to be adjusted. Adjustment includes the following steps:

[0094] Step 1: After the robot is powered on, press the reset button in the control circuit board on each support arm. The joints of the robot will move until the zero position switch is triggered. At this time, each joint is defined as being in the joint zero position.

[0095] Step 2: Place the robot on the ground, so that the support arm A1000, the support arm B2000 and the support arm C3000 are in contact with the ground. At this time, the support arm D4000 is vertically upward.

[0096] Step 3, loosen the top screws 1400 in the support arms A1000, B2000 and C3000 in turn, and adjust the circumferential position of the swing joint 1300 relative to the rotation axis 1110 in the rotation joint 1100, so that the swing planes of the support arms A1000, B2000 and C3000 are perpendicular to the ground, and the swing direction is toward the ground. After the adjustment is completed, re-tighten the top screw to lock the circumferential movement between the swing joint 1300 in the support arm and the rotation axis 1110 in the rotation joint 1100.

[0097] Step 4, loosen the top screw 1400 in the support arm D4000, adjust the circumferential position of the swing joint 1300 relative to the rotation axis 1110 in the rotation joint 1100, so that the swing plane of the support arm D4000 is perpendicular to the BC line, and the swing direction is toward the BC line. After the adjustment is completed, re-tighten the top screw to lock the circumferential movement between the swing joint 1300 in the support arm and the rotation axis 1110 in the rotation joint 1100.

[0098] Through the above connection and adjustment, the tetrahedron tumbling robot involved in the present invention is formed, and it is defined that the robot is in the initial state at this time. Figure 1 As shown, in the initial state of the robot, the straight lines where the four support arms are located converge at the central block 5000.

[0099] See also Figure 8 As shown, the tumbling motion of the tetrahedron tumbling robot involved in the present invention includes the following steps in one cycle:

[0100] Step 1: Starting from the initial state of the rolling cycle, the swing joints 1300 on the support arm A1000 and the support arm D4000 rotate through angles θ sA With θ sD After the swing joints reach the set angle, the robot rolls over with the line connecting the end points B and C of the support arm B2000 and the support arm C3000 as the axis. Figure 8 a)~8c).

[0101] Step 2: After the robot completes the roll, the swing joints 1300 on the support arm A1000 and the support arm D4000 move back by angles θ sA With θ sD , back to their respective joint zero positions. At this time, the straight lines where the four support arms of the robot are located converge again to the center block 5000, as shown in Figure 8 c)~8d).

[0102] Step 3: Control the rotation joints 1100 of the support arm B2000, the support arm C3000 and the support arm A1000 to rotate through angle θ rB ,θ rC With θ rA The swing planes of support arm B2000 and support arm C3000 are made perpendicular to the ground again, and the swing plane of support arm A1000 is perpendicular to the next rolling axis and the swing direction is toward the next rolling axis. Taking CD as the next rolling axis as an example, the swing plane of support arm A1000 is turned from perpendicular to the BC line to perpendicular to the CD line through the movement of the rotation joint 1100 of support arm A1000, and the swing direction is toward the CD line, as shown in FIG. Figure 8 d)~8e).

[0103] The above steps complete a tumbling motion of the tetrahedron tumbling robot involved in the present invention, and the state of the robot at this time serves as the initial state of the next tumbling motion. Figure 8 e) with Figure 8 a) It can be seen that after a rolling cycle, the position and orientation of the robot on the ground have changed, but the relative position relationship between the support arms has not changed. Figure 8 e) The support arms BDCA are mapped to Figure 8 The support arm ABCD in a) can be used without modification using the above rolling steps 1 to 3 (similarly, if the subsequent rolling axis is selected as the BD line, the support arm CBDA is mapped to Figure 8 a) in the support arm ABCD; if the subsequent rolling axis is selected as the BC line, the support arm DCBA is mapped to Figure 8 The supporting arm ABCD in a). After multiple tumbling cycles, the robot can complete directional movement on the ground.

[0104] The following specifically describes a method for optimizing the motion joint parameters of a tetrahedron tumbling robot. Fig. 9 As shown, the following steps are included:

[0105] Step 1, such as Fig.10 The characteristic parameters of the tetrahedron tumbling robot in the present invention are as shown in the figure, which are: the length from the center of the robot to the rotation axis of each support arm swing joint -r, the length from the axis of each support arm swing joint to the end -l, the mass contained in the sphere with a radius of r from the center of the robot -m center , the mass contained in each support arm outside the radius r from the center of the robot - m leg , each support arm swings the joint axis to m leg Distance to the center of mass - l c And the maximum angle of the robot's swing joint -θ max .

[0106] Step 2: Set the robot’s swing joint range [0,θ max ] is divided into the minimum unit of the required angle control accuracy Δθ, thereby obtaining a series of discrete angle values ​​on a single swing joint Define the swing joint angle of support arm A as θ sA , the swing joint angle of the support arm D is θ sD . Let the ordered pair (θ sA ,θ sD ) constitutes a set Θ, whose elements uniquely determine the shape of the robot on the ground in the rolling step 1. The number of pairs (θ) in Θ that satisfy the robot's rolling condition f is called sA ,θ sD ) constitutes a new set The robot's tumbling shape.

[0107] Specifically, the robot rolling condition f is determined by the following formula:

[0108]

[0109] Among them, x center is the distance between the projection of the spatial position of the robot center block on the ground and the line connecting the rolling axis BC, x ic It is the distance between the projection of the center of mass of the support arm on the ground and the BC line. On the ground, when a point is on the same side of the BC line as point A, the distance value of the point is negative. On the contrary, when a point is on the opposite side of the BC line as point A, the distance value of the point is positive.

[0110] Step 3, judgement like is an empty set, return to step 1 and adjust the characteristic parameters of the robot; if If not empty, proceed to the next step.

[0111] Step 4: For a specific swing joint angular velocity Create a mapping The mapping will The elements in (θ sA ,θ sD ) is mapped to the duration t (in seconds), and the set The whole is mapped to the set T.

[0112] Specifically, the mapping The relationships established are:

[0113]

[0114] Among them, θ flip =arctan(y D / xD ) is the total angle of rotation of the robot around the rolling axis BC during the rolling process, y D The end point D of the support arm D is (θ sA ,θ sD ) shape from the ground, x D is the distance from the projection of point D on the ground to the rolling axis BC; ω is the angular velocity of the robot's swing joint Under the condition of moving to (θ sA ,θ sD ) when the robot's overall mass center is around the rolling axis BC axis; m equ is the total mass of the robot; g is the acceleration due to gravity; l equ is the distance between the robot's overall center of mass and the rolling axis BC at this time; J is the robot's moment of inertia around the rolling axis BC at this time.

[0115] Step 5: Get the minimum element in the set T, and use its inverse mapping to get the angular velocity of the swing joint Under the condition, the angle θ required for the support arm A and the support arm D of the robot to move in the rolling motion sA With θ sD .

[0116] Step 6: Determine θ rB With θ rC During the robot's rolling motion, θ rB With θ rC The angle is updated based on the base value of the joint itself, specifically; θ rB The relationship between the new value of and its old value is: rB_new =mod(θ rB_old +120°,360°);θ rC The relationship between the new value of and its old value is: rC_new =mod(θ rC_old -120°,360°).

[0117] Step 7, determine θ rA During the robot's rolling motion, θ rA The angle is updated based on the base value of the joint and is related to the direction of travel selected later. Specifically, when CD is used as the next rolling axis, θ rA_new =mod(θ rA_old -120°, 360°); when BD is used as the next rolling axis, θ rA_new =mod(θ rA_old +120°,360°); when BC is used as the next rolling axis, θ rA_new =θ rA_old .

[0118] At this point, the determination of the motion joint parameters required for the robot during tumbling motion has been completed.

[0119] Example 1: r = 70 mm, l = 244 mm, m center =372g,m leg =48g,l c =122mm,θ max =120°,Δθ=1°, The robot starts from the initial state and will roll around CD in the next step. The above joint parameter optimization method can be used to obtain: θ sA =98°、θ sD =63°,θ rB =120°,θ rC =240°,θ rA =240°.

[0120] Example 2: Take r = 70mm, l = 244mm, m center =372g,m leg =48g,l c =122mm,θ max =120°, Δθ=1°, The robot starts from the initial state and will roll around CD in the next step. The above joint parameter optimization method can be used to obtain: θ sA =101°、θ sD =100°,θ rB =120°,θ rC =240°,θ rA =240°.

[0121] In summary, the present invention proposes a method for optimizing the motion joint parameters of a tetrahedron tumbling robot, which can enable the corresponding tetrahedron tumbling robot to perform periodic and continuous tumbling, thereby achieving directional motion. The proposed method is based on the joint angular velocity determined by the robot motor performance. Under this condition, a reasonable joint motion target can be given, so that the robot spends the shortest time in its tumbling motion, thereby improving the robot's motion efficiency.

[0122] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for optimizing the motion joint parameters of a tetrahedron tumbling robot, characterized in that: Applied to a tetrahedron tumbling robot, the tetrahedron tumbling robot comprises a support arm A (1000), a support arm B (2000), a support arm C (3000), a support arm D (4000) and a central block (5000); The support arm A (1000) comprises a rotating joint (1100), a swinging joint (1300) and a control circuit board (1800); the rotating joint (1100) and the swinging joint (1300) are respectively provided with a motor (1107); the motor (1107) is used to control the angles of the rotating joint (1100) and the swinging joint (1300); The support arm B (2000), the support arm C (3000) and the support arm D (4000) have the same structure as the support arm A (1000); The rotating joints (1100) on the supporting arm A (1000), the supporting arm B (2000), the supporting arm C (3000) and the supporting arm D (4000) are respectively connected to the central block (5000); The control circuit board (1800) controls the rotation of the rotary joints (1100) and the swing joints (1300) on each support arm to achieve the tumbling movement of the robot; In the rotary joint (1100), a joint cover (1105) is provided to mount the motor (1107) in the joint seat (1101), and transmit power to the rotating shaft (1110) through the worm gear structure; Bolt a (1102), bolt b (1103A), nut b (1103B), bolt c (1106A) and nut c (1106B) are provided to fix the joint cover (1105) and the joint seat (1101); A zero position baffle (1113) is provided on the rotating shaft (1110). When the rotating shaft (1110) rotates to a certain position, the zero position baffle (1113) triggers a zero position switch (1104) on the rotating joint (1100); The bolt (d1111) is installed in the threaded hole on the front side of the joint seat (1101). After being screwed in, a portion of the threaded section enters the hole of the worm (1108A), which is used to assist in supporting the worm (1108A) and reduce the deformation caused by the radial force of the worm wheel (1108B) on the worm (1108A); The motion joint parameter optimization method comprises: Determine the characteristic parameters of the tetrahedron tumbling robot; According to the robot's rolling condition f, filter out the shape that can make the robot roll The set composed ;in, is the swing joint angle of support arm A, is the swing joint angle of the support arm D; like If it is an empty set, the characteristic parameters of the tetrahedron tumbling robot are readjusted; like If not empty, calculate Medium Element At a specific swing joint angular velocity Next, the time t taken by the tetrahedron tumbling robot to complete the tumbling; According to the minimum value of the rolling time t, the angular velocity of the tetrahedron rolling robot at a specific swing joint is determined. The corresponding and ; Determine the angle of rotation of the rotation joint of support arm B and the angle of rotation of the rotating joint of the support arm C , during the robot's tumbling motion, and The angle is updated based on the base value of its own joint; The angle of rotation of the rotation joint of support arm A ; in, The relationship between the new value of and its old value is: The relationship between the new value of and its old value is: Determine the angle of rotation of the rotation joint of support arm A , during the robot's tumbling motion, The angle is updated based on the base value of its own joint and is determined according to the subsequent rolling axis of the tetrahedron rolling robot. ; The characteristic parameters of the robot include: the length r from the center of the robot to the rotation axis of each support arm swing joint, the length l from the axis of each support arm swing joint to the end, the mass contained in the sphere with a radius of r from the center of the robot , the mass contained in each support arm outside the radius r from the center of the robot , each support arm swing joint axis to The distance to the centroid And the maximum angle of the robot's swing joint ; The robot's rolling condition f is determined by the spatial position of the robot's central block, the spatial position of the center of mass of each support arm of the robot, ,as well as The formula for the rollover condition f is determined jointly by: in, is the distance between the projection of the spatial position of the robot center block on the ground and the line connecting the rolling axis BC, is the distance between the projection of the center of mass of the support arm on the ground and the line connecting BC; Medium Element At a specific swing joint angular velocity Under this condition, the calculation formula of the time t taken by the tetrahedron tumbling robot to complete the tumbling is: in, is the total angle of rotation of the robot around the rolling axis BC during the rolling process, , The end point D of the tetrahedron tumbling robot support arm D is The height of the shape from the ground. is the distance from the projection of point D of the tetrahedron tumbling robot on the ground to the tumbling axis BC; is the angular velocity of the tetrahedron tumbling robot during the swing joint Conditions of movement The angular velocity of the robot's overall mass center around the rolling axis BC axis at time; is the total mass of the tetrahedron tumbling robot; g is the acceleration due to gravity; is the distance between the center of mass of the tetrahedron tumbling robot and the tumbling axis BC at this time; J is the moment of inertia of the tetrahedron tumbling robot around the tumbling axis BC at this time.

2. The method according to claim 1, characterized in that The rotary joint (1100) is provided with a rotating shaft (1110); The rotary joint (1100) is connected to the swing joint (1300) via a thrust bearing (1200), a top screw (1400) is provided to fix the circumferential rotation angle of the swing joint (1300) relative to the rotating shaft (1110) of the rotary joint (1100), and a double nut (1500) is used to fix the axial position of the swing joint (1300) relative to the rotary joint (1100).

3. The method according to claim 2, characterized in that The support arm A (1000) further comprises a support arm structural plate (1600) and a circuit board bracket (1700); The circuit board bracket (1700) is arranged on the support arm structure plate (1600); the control circuit board (1800) is arranged on the circuit board bracket (1700); the control circuit board (1800) is used to receive rotation angle signals transmitted by the motors (1107) in the rotating joint (1100) and the swinging joint (1300), and to control the angles of the motors (1107) in the two joints; The support arm structure plate (1600) is mounted on the rotating shaft (1110) of the swing joint (1300).

4. The method according to claim 1, characterized in that: The control circuit board (1800) comprises a reset button 1, a reset button 2, a wireless communication module, a power module, a microcontroller and a motor drive module. The control circuit board (1800) is connected to a zero position switch (1104) and a motor (1107) in a rotating joint (1100) and a swing joint (1300) in the same support arm; The microcontroller is connected to an external host computer; The power supply module is used to supply power to the other modules, and the wireless communication module is used to control the information exchange between the microcontroller in the support arm and the host computer; The microcontroller is used to send corresponding control instructions to the motor drive module according to the instructions of the host computer; the motor drive module is used to control the motors (1107) in the rotating joint (1100) and the swinging joint (1300) respectively according to the control instructions; The reset button is used to calibrate the joints after the robot is powered on for the first time.

5. The method according to claim 1, characterized in that The angle of rotation of the rotating joint of the support arm A The relationship between the changing rule of and the subsequent rolling axis selected by the tetrahedron rolling robot is as follows: When CD is used as the next rolling axis, ; When BD is used as the next rolling axis, ; When BC is used as the next rolling axis, .

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