| With the gradual maturity of science and technology,more and more fields begin to use robots to replace human work.At present,robot technology is widely used in industrial fields,such as cargo handling,welding and other fields.In recent years,because of an agricultural development,from the agricultural planting,pruning to late maintenance and harvest requires enormous resources,therefore,in order to better help the development of agricultural products,the liberation of human hands,industrial robot has been applied to agricultural harvest field help even complete related work instead of humans.At present,agricultural picking robots applied in the field of agriculture basically add a mechanical arm structure to the wheeled or tracked mobile mechanism to complete fruit picking.The advantage is that the picking is stable,but the deficiency is that it is difficult to pick in a narrow space and lacks flexibility.In view of this problem,In this paper,a humanoid picking robot which is more flexible in structure and more extensive in application environment has been studied tentatively.At present,the mechanical arm of picking robot is generally 4 degrees of freedom and 6 degrees of freedom,and its picking space and flexibility are relatively small.Therefore,this paper studies the humanoid picking robot.The upper limb and lower limb of the robot are both 7 degrees of freedom,so that it has better flexibility and improves the picking range.Secondly,for the humanoid picking robot,the key is to ensure that its picking process can follow the optimal picking trajectory;In addition,ensuring the stability of movement in the maximum picking range is the key to fruit picking.Therefore,this paper focuses on the above three issues.First of all,by means of optical motion capture the experimental data obtained in the process of human movement,this article designed to sync speed under the gait of a human body movement and the different height and different direction on human grasp ball movement data acquisition,body movement in the process of rotation Angle of each joint and the joint torque value,provide reference for subsequent dynamics simulation data.Then,based on the principles of human anatomy,a three-dimensional model of humanoid picking robot was established.According to the model,the gait motion planning was carried out and the gait motion process was simulated.The results showed that the maximum torques on the hip joint,knee joint and ankle joint were: In 1480N·mm,1240N·mm and 585N·mm,the relative errors of hip joint and knee joint torque values and experimental values were 6.7% and 9.6%,respectively.The simulation results were within the error range of experimental data,which verified the validity of the model.The results showed that the modeling process in this paper was reasonable and could be used to continue the follow-up research on the picking process of humanoid picking robot.The kinematics model of the 7-DOF humanoid manipulator was established for kinematics analysis and verification,and the workspace of the 7-DOF and 6-DOF humanoid manipulator was analyzed by Monte Carlo method.The workspace range of the 7-DOF humanoid manipulator in X,Y and Z directions was-89.24～89.54 cm,respectively.-87.23～90.75 cm,-89.98～66.62 cm,the working space range of 6-DOF humanoid manipulator in X,Y and Z direction is-74.78～74.2cm,-70.85-74.02 cm,-73.54-57.53 cm,The results show that the 7-DOF humanoid manipulator has a larger range of picking space than the 6-DOF humanoid manipulator.Based on the minimum energy method "to the selection of the optimal solution of joint Angle,and the optimal value polynomial interpolation trajectory planning,the paper respectively using polynomial and cubic polynomial or five times the 3-5-3piecewise polynomial interpolation for trajectory planning,based on polynomial interpolation,according to the results of three times polynomial interpolation,the polynomial interpolation and five times the 3-5-3 piecewise polynomial interpolation,When the joint Angle has the same variation range,the variation range of angular velocity and angular acceleration is different,and the variation range of angular acceleration is-1.571～1.571rad/s,-3.719～8.165rad/s,-0.3664～0.3664rad/s,and the variation range of angular acceleration is:-6.283～6.283 rad/s2,-25.15～25.15 rad/s2and-0.4725～0.4725rad/s2 indicate that the velocity and acceleration fluctuation range of 3-5-3 piecewide polynomial interpolation is small,and the end movement of the picking manipulator is more stable and can be optimized to complete the trajectory planning.Of biggest harvest finally,through the center of gravity projection method within the scope of the stability of the humanoid picking robots are studied by the multi-body dynamics simulation software boundary location humanoid picking stability analysis for the picking motion of the robot,to obtain the biggest harvest range torque of each joint,shoulder joint,elbow and wrist joint torque size are: Based on the experimental results of 8750N·mm,1920N·mm and 412N·mm,the relative errors between the simulation value and the experimental value are 5.2%,7.6% and 9.8%,respectively.The results show that the humanoid picking robot can achieve stable picking within the maximum picking range,which lays a foundation for the motion control of the humanoid picking robot in the future... |
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