A spatial redundantly actuated parallel mechanism (RAPM) constrained by two point-contact higher kinematic pairs (HKPs) has been designed for food texture evaluation during the mastication process. To this end, the mechanism must be capable of reproducing complex mandibular behaviours of human subjects in a biomimetic manner with satisfied motion accuracy. In this paper, first, the mechanism is described in detail, then elastodynamic behaviours of this mechanism are investigated based on the kineto-elastodynamics (KED) method and are formulated as a system of stiff ordinary differential equations. Due to the constraints of two HKPs onto the mandible, the derived mass matrix contains unknown generalized coordinates. This matrix is significantly different from those of parallel mechanisms (PMs) via the KED method in the literature. Third, the distributed torque under five performance criteria is employed as a feedforward to investigate its elastodynamic performance in two case studies, namely, without and with bite force onto the molar, respectively, given that the mechanism is specified to track a real human mandibular movement. The role of the damping effect in influencing vibrations is also studied. Finally, to explore the role of redundant actuations in elastodynamics, a non-redundantly actuated counterpart is proposed, where the aforementioned procedure is implemented. Results illustrate that the RAPM owns the satisfied elastodynamic performance in small vibrations, large stiffness and high natural frequency. Meanwhile, the damping effect can change the vibration distribution among different optimal torque criteria. It also shows that the RAPM outperforms its counterpart in the elastodynamic performance.

设计了受两个点接触高级运动学对（HKP）约束的空间冗余致动并联机构（RAPM），用于在咀嚼过程中评估食物质地。为此，该机构必须能够以仿生方式以令人满意的运动精度再现人类对象的复杂下颌行为。在本文中，首先详细描述了该机制，然后基于动弹性-动力学（KED）方法研究了该机制的弹性动力学行为，并将其表述为刚性常微分方程组。由于两个HKP约束在下颌骨上，因此导出的质量矩阵包含未知的广义坐标。该矩阵与文献中通过KED方法的并行机制（PM）的矩阵显着不同。第三，假设指定了跟踪真实人体下颌骨运动的机制，在五个案例中采用了五种性能标准下的分配扭矩作为前馈，以研究其弹性动力学性能。还研究了阻尼效应在影响振动中的作用。最后，为了探索冗余致动在弹性动力学中的作用，提出了一种非冗余致动的对应物，其中执行了上述过程。结果表明，RAPM在小振动，大刚度和高固有频率下具有令人满意的弹性动力学性能。同时，阻尼效果可以改变不同最佳扭矩标准之间的振动分布。