Motion Analysis And Control System Design Of A Three-fingered Metamorphic Robotic Hand

The most important feature of the three-fingered metamorphic hand compared with the traditional dexterous hand is the introduction of a metamorphic palm.The metamorphic mechanisim applied to the multi-finger dexterous hand palm,which increases the dexterity and workspace of dexterous hand,improves the dexterous hand operation quality and adaptability to different shaped objects.The concept of the threefingered metamorphic hand is very different from the traditional dexterous hand,which is very innovative in structural design and provides a new idea for the design of other dexterous hands.However,the introduction of a metamorphic palm in the threefingered metamorphic hand also adds to the challenge of dexterous hand motion analysis and the difficulty of designing dexterous hand control system.The main research contents of this paper are the motion analysis of the three-fingered metamorphic hand and the design of the three-fingered metamorphic hand control system,as follows:(1)The palm of three-fingered metamorphic hand is a parallel mechanism,the fingers are serial mechanism,the whole three-fingered metamorphic hand belongs to series-parallel mechanism,there is no existing common analytical methods.According to the special structure of three-fingered metamorphic hand,a new method by using the spherical triangular sine and cosine theorem to obtain the palm forward position kinematics of three-fingered metamorphic hand.Based on this,performing the matrix method,the forward position kinematics model and inverse position kinematics model of the hand is revealed.(2)By applying the screw theory to establish the forward velocity kinematics model of the three-fingered metamorphic hand.Based on this,the inverse velocity kinematics model of the three-fingered metamorphic hand is obtained by using the method of reciprocal screw theory of the screw theory.The screw theory is simple and has obvious advantages in velocity analysis of the three-fingered metamorphic hand.(3)The workspace of the three-fingered metamorphic hand is obtained for the first time,and intuitive display of hand workspace augmentation effect,due to the introduction of a metamorphic palm for the three-fingered metamorphic hand.Further,by using the differential transformation method,the Jacobian matrix of the three-fingered metamorphic hand is obtained,and the hand statics model is established.At the same time,using the Lagrange theory,the dynamic equations of the finger mechanical linkage are established,and the dynamical model of the DC motor used in the three-fingered metamorphic hand is established.The dynamics of the three-fingered metamorphic hand is established.(4)The control system of three-fingered metamorphic hand is designed from the control system hardware configuration,control system software and control algorithm.According to the special structure of dexterous hand,the method of combining the position sensor and spring is proposed to obtain force information of the three-fingered metamorphic hand,and to obtain force information of the three-fingered metamorphic hand through the real-time current of the motor.Furthermore,the control of the threefingered metamorphic hand was transplanted into the ROS environment,and the system control of the three-fingered metamorphic hand based on ROS was realized.In this paper,the position kinematics model and velocity kinematics model of the three-fingered metamorphic hand are analyzed,and the conclusion of the analysis is applied in the three-fingered metamorphic hand PID position control.The statics,dynamics analysis of the three-fingered metamorphic hand are analyzed,and the conclusion of the analysis is applied in the three-fingered metamorphic hand force control,and in the final having the three-fingered metamorphic hand grasping experiments.