Junji Hirai

About

Junji Hirai is a robotics and control systems engineer whose research spans wireless power transmission, fault-tolerant control, rehabilitation robotics, and mobile robot navigation. His most influential contribution, published in 1996 and accumulating 102 citations, introduced a groundbreaking contactless power and information transmission system using a single high-frequency resonant AC link inverter — a pioneering advance that enabled decentralized, cable-free control of robot manipulators. This work laid conceptual groundwork for modern wireless power applications in industrial automation, further extended in subsequent publications on inductive transmission for reconfigurable manufacturing systems. Hirai has also made meaningful contributions to medical robotics, developing a biofeedback therapeutic exercise manipulator capable of estimating joint torque and muscle force without relying on electromyography, earning 59 citations and offering practical improvements to physical rehabilitation quality. His work on fault-tolerant control of flexible robotic arms using reaction force observers, cited over 50 times, addresses critical reliability challenges in computer-controlled systems. Additional contributions include image-based navigation for nonholonomic mobile robots and bilateral teleoperation under communication delay. Across these domains, Hirai's research consistently bridges theoretical control engineering with real-world robotic applications in industrial and clinical settings.

Research Focus

Key Achievements

Top Papers

1. 1
   Wireless transmission of power and information through one high-frequency resonant AC link inverter for robot manipulator applications

   102 citations · 1996
2. 2
   Development of a Biofeedback Therapeutic-Exercise-Supporting Manipulator

   59 citations · 2009
3. 3
   Fault-Tolerant Control System of Flexible Arm for Sensor Fault by Using Reaction Force Observer

   50 citations · 2005
4. 4
   Decentralized control of machines with the use of inductive transmission of power and signal

   21 citations · 2002
5. 5
   Fault-tolerant control system of flexible arm for sensor fault by using reaction force observer

   11 citations · 2004
6. 6
   Development of a Biofeedback Therapeutic Exercise Supporting Manipulator for Lower Limbs

   10 citations · 2006
7. 7
   Image feature based navigation of nonholonomic mobile robots with active camera

   10 citations · 2007
8. 8
   Stability and transparency of adaptive controller based four-channel bilateral control system with communication delay

   9 citations · 2014
9. 9
   Wireless transmission of power and information through one high frequency resonant AC link inverter for robot manipulator applications

   8 citations · 2002
10. 10
    Preliminary study on robotic exercise therapy

    8 citations · 2005

Key Collaborators

Contact & Links