An optimal control strategy for hybrid actuator systems: Application to an artificial muscle with electric motor assist

Ishihara, Koji; Morimoto, Jun

doi:10.1016/j.neunet.2017.12.010

Cited by 17 publications

(31 citation statements)

References 11 publications

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“…It was found that fatigue of forearm muscles developed when the subject continued to control the nger position with EMG signals of the muscles. An optimal control strategy for a pneumatic rubber actuator (the static actuator) has been developed for an assistive robot [21]. A control strategy both for the static and astatic actuators for an actual articial muscle is desirable.…”

Section: Discussionmentioning

confidence: 99%

A Mathematical Model of the Dynamic Force–length Relationship of Skeletal Muscle Operating on Ascending and Descending Limbs

Akazawa

2019

ABE

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A new Hill-type model of skeletal muscle contraction referred to as the SL/ST model is proposed based on recent physiological ndings: intact human skeletal muscles operate on the ascending limb (hereinafter referred to as the as-limb) and the descending limb (ds-limb) of the isometric force-length relationship; and stretch-evoked force enhancement (ST-enhancement) is found on the ds-limb. Dynamic behaviors differ remarkably between the two limbs. The model has two modes: a sliding lament mode (SL mode) and a stretch-evoked force enhancement mode (ST mode). The SL mode operates on the as-limb, and on the ds-limb when the muscle is shortening, while the ST mode operates when ST-enhancement occurs in the ds-limb. Transient force responses of the model to length perturbations were similar to those of frog semitendinosus muscles in vitro. Length responses to step change in load of the model suggest that the muscle is unstable and not static in SL mode on the ds-limb, while it is stable and static in SL mode on the as-limb and in ST mode on the ds-limb.

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Section: Discussionmentioning

confidence: 99%

A Mathematical Model of the Dynamic Force–length Relationship of Skeletal Muscle Operating on Ascending and Descending Limbs

Akazawa

2019

ABE

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“…However, just compensation is not enough for a dynamic swing. In another study, an optimal control strategy in which a different bandwidth between pneumatic and electric control was proposed [20]. An optimal control method may be suitable for dynamic swing motion.…”

Section: B Hybrid Controlmentioning

confidence: 99%

High-Speed Humanoid Robot Arm for Badminton Using Pneumatic-Electric Hybrid Actuators

Mori

Tanaka

Nishikawa

et al. 2019

IEEE Robot. Autom. Lett.

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We describe the development of a robot configured to play badminton, a dynamic sport that requires high accuracy. We used pneumatic-electric hybrid actuators, each combining a pneumatic actuator, with high-speed and lightweight attributes, and an electric motor with good controllability. Our first objective was to develop hybrid actuators that are lightweight and compact and with integrated sections. Using parts made of lightweight materials such as plastics and aluminum coils, and using wire for power transmission, we made actuators much lighter and smaller than previous ones. In addition, for high accuracy and power, tension sensor units and a heat countermeasure mechanism were also incorporated. As practice partners, we consider badminton robots to be more useful if they were humanoid in appearance and have a variety of shots. We, therefore, developed a humanoid robot arm. By incorporating actuators as link structures, the overall weight was reduced, and both complex degrees of freedom (DoFs) and a large range of motion were realized. Subsequently, we developed a robot with seven DoFs, three DoFs for the shoulder, two for the elbow, and two for the wrist, similar to the configuration of human arms. The robot, therefore, roughly reproduces human movements. At 19 m/s, the maximum speed of the racket was quite fast. The hybrid control reduced the motion variance, allowing improvements in accuracy of more than three times that of motions with only pneumatic control. In addition, performing path planning and tracking control with high precision was possible, tasks that are difficult for conventional pneumatic dynamic robots. Index Terms-Hydraulic/pneumatic actuators, mechanism design, tendon/wire mechanism, humanoid robots, motion control. I. INTRODUCTION S PORT is a global business and expected to be a popular field for robot applications. With the recent developments in robot technology, robots are helping humans to play sports, specifically in regard to retaining and training professional athletes [1]. For other sports such as football [2], table tennis [3], and

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“…Since the introduction of the HPEA idea in 1987 [4], different designs have been proposed to develop this type of actuator. They include a combination of a DC motor and a rotary pneumatic motor 2 of 15 in parallel [5], pneumatic muscle actuators (PMA) with a DC motor [2,[6][7][8], pneumatic cylinders with a DC motor [9,10], and a pneumatic cylinder integrated within a linear motor [11,12].…”

Section: Introductionmentioning

confidence: 99%

“…Although there have been some papers focused on position controller design for HPEAs [3,6,10], very few have used a controller that incorporates each actuator's characteristics and studied the allocation problem alongside the position control problem. In [7], an optimization method is proposed for the torque allocation of a HPEA consisting of a PMA and an electric motor. They proposed a two-stage optimization approach that can be used for redundant actuators that consist of a higher bandwidth actuator and a lower bandwidth one.…”

Section: Introductionmentioning

confidence: 99%

Optimal Force Allocation and Position Control of Hybrid Pneumatic–Electric Linear Actuators

Rouzbeh

Bone

2020

Actuators

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Hybrid pneumatic–electric actuators (HPEAs) are redundant actuators that combine the large force, low bandwidth characteristics of pneumatic actuators with the large bandwidth, small force characteristics of electric actuators. It has been shown that HPEAs can provide both accurate position control and high inherent safety, due to their low mechanical impedance, making them a suitable choice for driving the joints of assistive, collaborative, and service robots. If these characteristics are mathematically modeled, input allocation techniques can improve the HPEA’s performance by distributing the required input (force or torque) between the redundant actuators in accordance with each actuator’s advantages and limitations. In this paper, after developing a model for a HPEA-driven system, three novel model-predictive control (MPC) approaches are designed that solve the position tracking and input allocation problem using convex optimization. MPC is utilized since the input allocation can be embedded within the motion controller design as a single optimization problem. A fourth approach based on conventional linear controllers is included as a comparison benchmark. The first MPC approach uses a model that includes the dynamics of the payload and pneumatics; and performs the motion control using a single loop. The latter methods simplify the MPC law by separating the position and pressure controllers. Although the linear controller was the most computationally efficient, it was inferior to the MPC-based controllers in position tracking and force allocation performance. The third MPC-based controller design demonstrated the best position tracking with RMSE of 46%, 20%, and 55% smaller than the other three approaches. It also demonstrated sufficient speed for real-time operation.

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An optimal control strategy for hybrid actuator systems: Application to an artificial muscle with electric motor assist

Cited by 17 publications

References 11 publications

A Mathematical Model of the Dynamic Force–length Relationship of Skeletal Muscle Operating on Ascending and Descending Limbs

A Mathematical Model of the Dynamic Force–length Relationship of Skeletal Muscle Operating on Ascending and Descending Limbs

High-Speed Humanoid Robot Arm for Badminton Using Pneumatic-Electric Hybrid Actuators

Optimal Force Allocation and Position Control of Hybrid Pneumatic–Electric Linear Actuators

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