一种串联张紧式恒力矩机构设计及实验研究

Design and Experimental Research of a Tandem Tensioning Constant-Torque Mechanism

设计了一种串联张紧式恒力矩机构.恒力矩机构的作用是吸收电机在高频冲击下的响应滞后,被动保持吊索恒定张力.旁路张紧式恒力机构存在吊索在滑轮处压迫变形导致的摩擦问题.要避免这种摩擦带来的能量损耗,选择使用不含滑轮的串联张紧式恒力矩机构.从做功-储能观点,恒力矩机构是具有恒定的储能-转角比例的储能机构.基于此观点,提出压簧-凸轮-扭杆和压簧-扭杆两种恒力矩机构方案,分别对其进行原理分析和理论验证.综合比较后选择摩擦和转动惯量更小的压簧-扭杆式方案进行机构设计、仿真验证和实验验证.此机构形式简单,占用空间尺寸为1000 mm×350 mm×350 mm,实验证明,此机构等效刚度为1.47 N/mm,静态工作点调节范围为0~1000 N,正反向误差为±15 N.

A tandem tensioning constant-torque mechanism is designed. A constant-torque system is used to absorb the response lag of motor under the high-frequency impact and keep the constant tension of the string passively. In the by- pass tensioning constant-force mechanism, the friction problem exists because of sling＇s compression deformation on the pulley. To avoid this kind of energy loss caused by friction, the tandem tensioning constant-torque mechanism without pul- ley is selected. From the view of working-energy storage, the constant-torque mechanism is an energy storing mechanism with constant proportion of energy storage-angle. Based on this viewpoint, both pressure spring-cam-torsion bar and pres- sure spring-torsion bar constant-torque mechanisms are proposed. Then the principle analysis and theoretical validation are performed respectively. The mechanism design, simulation and experimental validation are conducted on the pressure spring- torsion bar constant-torque mechanism with smaller friction and moment of inertia after the comprehensive comparison. This simple mechanism takes up the spatial size of 1000 mm x 350 mm x 350 mm. The experiments prove that the mechanism＇s equivalent stiffness is 1.47 N/mm, adjusting range of the static working point is 0N1000 N, and the positive and negative error is 5：15 N.