Configuration Principle And Kinematic Characteristics Of Underactuated Bionic Spine Mechanism

The spine is an important feature of higher organisms,which plays an important role in supporting the torso,storing and transferring energy,improving energy utilization,ensuring flexibility and stability,and the mechanical bionic spine has important applications in bionic robots such as quadruped robots,underwater robot fish,and flexible robotic arms.The existing bionic spine mechanism has many problems such as complex structure,difficult control,and too many actuators.Therefore,it is important to study the simple control and rapid response of the less-actuated multi-joint bionic spine mechanism to improve the performance of bionic robots.The discrete and continuous bionic spine mechanism based on the nonlinear transmission characteristics of noncircular gears is proposed,and the structural composition and motion principle of the mechanism are clarified.The correspondence between joint bending angle,cord extension/contraction variation and the non-cylindrical gear ratio is established.The non-cylindrical gear knuckle curve model is solved to coordinate the bending motion of the bionic spine mechanism.In order to solve the joint coupling problem arising from the discrete and continuous multi-joint bionic spine mechanism during the motion,the decoupling method of the multi-degree-of-freedom bionic spine mechanism is proposed by combining the Bowden line drive method.Further,the motion trajectory and workspace model of the two-degree-of-freedom bionic spine mechanism were obtained by calculating the position coordinates of each joint node during the motion of the discrete and continuous multi-joint bionic spine mechanism.The two-degree-of-freedom bionic spine mechanism has a wider driving range and better overall flexibility than the single-degree-of-freedom bionic spine mechanism.Finally,a prototype of the discrete two-degree-of-freedom bionic spine mechanism based on a non-circular gear drive was designed and prototyped,and its bending motion tests were conducted under various working conditions.