Parkinson’s disease (PD) is one of the most common neurodegenerative diseases. To date, among medications used to treat PD, only levodopa exhibits a limited disease-modifying effect on early-onset PD, but it cannot delay the progression of the disease. In 2018, for the first time, the World Health Organization included traditional Chinese medicine (TCM) in its influential global medical compendium. The use of TCM in the treatment of PD has a long history. At present, TCM can help treat and prevent PD. Iron metabolism is closely associated with PD. Ferroptosis, which is characterized by the accumulation of lipid peroxides, is a recently discovered form of iron-dependent cell death. The research literature indicates that ferroptosis in dopaminergic neurons is an important pathogenetic mechanism of PD. TCM may thus play unique roles in the treatment of PD and provide new ideas for the treatment of PD by regulating pathways associated with ferroptosis.

In order to decrease the backward motion and improve the motion efficiency, a walking type piezoelectric actuator has been proposed with two ‘legs’ based on the parasitic motion of obliquely assembled PZT stacks. The structure and motion principle of the proposed walking type piezoelectric actuator are described, and its experiment system is set up. Experimental results indicate the proposed piezoelectric actuator could reduce the backward motion effectively. The minimum backward rate α= 2.26% is achieved under the condition of the phase difference θ= 180°, the input voltage U= 120 V and the input frequency f= 1 Hz; the minimum stepping displacement is 0.24 μm under the condition of U= 5 V, f= 1 Hz and θ= 180°; the maximum speed V max is 2472 μm s−1 under the condition of U =120 V and θ= 180°; the maximum vertical load force F Vmax = 6850 g under the condition of U = 120 V, f = 1 Hz and θ = 180°. Furthermore, a dynamic model of the whole walking type piezoelectric actuator is established, and it has been employed to simulate the motion of the proposed walking type piezoelectric actuator. Simulation results present a great agreement of experimental results. This study shows a novel idea for the design of piezoelectric actuators to eliminate the influence of backward motion and improve the output efficiency of the actuator.

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A walking type piezoelectric actuator with two umbrella-shaped flexure mechanisms is proposed to reduce the backward motion. By utilizing two umbrella-shaped flexure mechanisms which could be treated as two 'legs', the 'walking' motion is accomplished. The structure and motion principle are described; Finite Element Method (FEM) is exploited to explore the static and modal performances of the umbrella-shaped flexure mechanism. Moreover, experiments have been carried out to investigate the working performance of the proposed walking type piezoelectric actuator. Results show that the walking type piezoelectric actuator with umbrella-shaped flexure mechanisms could achieve the 'walking' motion and reduce the backward motion. Additionally, the phase difference between two input signals U 1 and U 2 greatly influences the working performance. In the case of the phase difference Φ = 95 • , the backward rate of the slider is able to achieve the minimum 0%; the minimum stepping displacement is 0.3 µm when the frequency f = 1 Hz; the maximum motion speed of the slider is up to 1132 µm s −1 when the input frequency f = 400 Hz and the input voltage U = 120 V; the maximum output force is 700 g while the input voltage U = 120 V and frequency f = 1 Hz.

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