| The complex terrain environment will affect the trafficability of the robot,and then increase the difficulty of robot detection.The symmetrical connecting rod shape-shifting mine detecting tracked robot,also called the shape-shifting tracked robot has great terrain adaptability.By controlling its own mechanism,the trafficability of the robot in different terrain is improved.Complex terrain can be simplified into typical structured terrain and its combination,such as slope,boss,independent step,continuous step and so on.Therefore,combined with the overall dimensions and mechanism characteristics of the shape-shifting tracked robot,the kinematics,dynamics and stability margin of the robot under typical structured terrain are analyzed,and the theoretical calculation data are obtained.The multi-body dynamics simulation model of the shape-shifting tracked robot is established to verify the correctness of the theoretical calculation,and finally the trafficability of the shape-shifting tracked robot is obtained.The main research contents include:(1)The main structure of shape-shifting tracked robot is introduced,including pitch differential balance adjustment device and four rod deformation device.The layout scheme of connecting rod in pitch differential balancing device is discussed,and the relationship between sliding table displacement,rotation angle of differential balancing rod and swing angle of single side walking part is deduced according to the relationship of spatial connecting rod.The relationship between the deformation angle of the active rod and the grounding angle and the maximum contact height of the inclined outer track in the four connecting rods deformation device is analyzed.(2)According to the discontinuous distribution of the front and rear tracks of the one-sided walking part,established the steering kinematics and dynamics model of the shape-shifting tracked robot on the slope plane terrain.The variation of turning radius and driving force of left and right walking parts with the yaw angle of robot rigid body relative to slope plane is analyzed.(3)Based on the geometric constraints between the front and rear tracks of the shape-shifting tracked robot and the steps,the whole process kinematics and dynamics analysis model of the robot climbing independent steps is established.Combined with the front and rear contact points between the crawler and the ground and the speed direction at the corresponding position,the support force and friction at the contact point are calculated,and finally the driving torque when one side crawler climbs an independent step is obtained.In addition,by controlling the deformation angle of the four connecting rod suspension of the walking part,combined with the geometric and stability constraints of the chassis and obstacles,the limit obstacle crossing performance of the robot facing independent steps,circular bosses and channels is analyzed;Thus,the change range of four connecting rod angle when the robot climbs obstacles of different sizes is obtained.(4)Based on the normalized dynamic energy stability margin,the stability margin of the shape-shifting tracked robot in the initial state and the influence of the deformation of the four connecting rods suspension on the stability margin on the left and right sides are analyzed.The body coordinate system and the left and right walking part coordinate system of the shape-shifting tracked robot are established.Based on this,the center of mass of the robot is synthesized and the position of the outermost contact point relative to the body coordinate system is calculated;The sensor coordinate system is established,and calculate the inertial force and moment at the center of mass of the robot;Finally,the standardized dynamic energy stability margin estimation model of shape-shifting tracked robot moving in rough terrain is established.The motion parameters obtained from the multi-body dynamics simulation of the robot are brought into the stability margin estimation model,and the change trend of the robot stability margin is obtained.In the simulation,the deformation angle of four connecting rods suspension is controlled according to different terrain environment,so as to improve the stability of the robot. |
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