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This paper describes a general theory for the characteristics of voltage-induction-type electrostatic motors (VITEMs). VITEMs are one of macro-scale electrostatic film motors with multi-phase electrodes on both the sliders and the stators. The motor drives synchronously without voltage feeding wires to its slider due to the indirect power supply using electrostatic induction. Although the numbers of electrode phases can be chosen arbitrary to realize the motor, the characteristics of the motors were analyzed only for two specific cases in the previous studies. This work extends the previously proposed theories so that they can handle a general case, in which the slider and the stator have m- and n-phase electrodes with arbitrary numbers for m and n. The theory can estimate the optimized thrust force performance for any electrode configurations, when given fundamental parameters regarding the capacitance coefficients of the motor, which can be obtained either experimentally or numerically. Using the proposed theory, several different configurations of VITEMs are analyzed and compared, in terms of thrust force performance. The results indicate that electrode thickness considerably affects the thrust force performance of VITEMs, which is not the case for other synchronous electrostatic film motors, and thus suggest that the design of VITEMs should more carefully consider the three-dimensional structure of the electrodes.

This paper describes the development of a SCARA-type haptic device, which will be used to assist a human operator in non-contact object handling of silicon wafers using electrostatic levitation. The device has three degrees of freedom, of which only one (vertical) is actively controlled. By utilizing the admittance control paradigm, a high vertical stiffness and a high output force can be achieved. These properties are necessary for the intended application of non-contact object handling to prevent instabilities (induced by the human motion) of the electrostatic levitation system. As the nominal air gap between object and electrostatic levitator is in the order of 350 micrometer, with an allowable position error of about 150 micrometer, instability can easily occur if there is no haptic assistance, especially in the picking up or placing process. The developed SCARA-type haptic device has a mechanical stiffness of 51 N/mm for the vertical direction when it is in the weakest posture, which is sufficient for the non-contact handling task. The design and performance of the haptic device for the active vertical degree of freedom are described in this paper.

Previous electroadhesive climbing robots generally employed typical electromagnetic motors, which spoiled some of the advantages of electroadhesion such as it being light, thin and flexible. To improve these, an integration of electrostatic actuation and adhesion was utilized in this work. By using FEM analyses, the present paper analysed the effect of design parameters on adhesive and driving forces respectively, and examined the possible interference between electrostatic actuation and adhesion inside the integration. Then this article discussed the driving force, payload capacity and torque balance of the robot with the integration. Based on these analyses, we designed and fabricated a lightweight (94 g) and low-height (15 mm) prototype with electrode films made by screen printing. Experiments on the prototype demonstrated that it can adhere to a vertical wall stably and move at a maximum speed of 35.3 mm/s.