Compact Rescue Robot Climbs Onto The Stage

A major feature of the National Science Foundation’s Engineering Research Center program is the emphasis on test beds. Test beds are primarily intended to provide:

1.) a means for demonstration of the applicability of research projects to real world applications and

2.) a guide the formation of additional research projects to meet the challenges seen in implementing relevant portions of the test bed’s functionality.

In addition, they illustrate the potential of fluid power to prospective students and excite their imagination for a career in the related areas. The CCEFP test beds are selected to collectively cover a broad range of power levels and Test Bed 4, the Compact Rescue Robot, represents applications in the 100W to 1 kW range, roughly human scale applications. In this range you will not find many current fluid power applications on the market and contrary to applications at a higher range of power, such as the excavator and passenger vehicle, the Center elected a more exotic application: a walking rescue robot with a large number of degrees of freedom and a limited market at this time. While this has endured some scrutiny from those involved in more conventional applications, a rescue robot epitomizes many challenges that can be found in this power range, and illustrates opportunities for some new products in the fluid power industry. Applications are envisioned in related areas such as service robots, assistive devices and construction and agricultural applications. The closest relevant devices employing fluid power at or near commercial availability include the Big Dog Robot1 by Boston Dynamics for rough terrain transport and the Bear Robot2 (battlefield extraction assistance robot) by VECNA Robotics that would indeed profit from improved compactness and efficiency.

The challenges foreseen for the CRR (Compact Rescue Robot) include efficient small scale generation of power, either pneumatic or hydraulic, effective control algorithms, especially for pneumatic servo control, and effective operator interfaces that must be substantially different than those for larger applications where the operator tends to be riding on the device.

The means of mobility a major decision point of CRR design. Why legs? In a rescue situation, it is anticipated that unstable debris, damaged stairways and obstacles in the path will be encountered. This is the situation reported in the Fukushima Dai-ichi nuclear reactor where four iRobot military robots of two designs have been modified for exploration of the high radiation areas of the plant. While rescue of victims is not the mission of these robots, gaining access to the points of interest in the plant is potentially very similar, since a hydrogen gas explosion in the plant has resulted in significant damage to the buildings. The PackBot and larger Warrior robots are treaded vehicles and operators report difficulty in climbing stairs, gaining traction, opening doors, and keeping upright.3 Operator experiences bluntly placed in a blog by one of the operators yields a realistic look at the challenges of operating a robot in a disaster scenario. A legged, compact, pneumatic or hydraulic robot would be able to address some of the issues that challenge the operators there.

Electric rescue robots are most commonly tracked or wheeled vehicles. Negotiating stairs and rugged terrain presents challenges for these “continuous contact” designs that legged locomotion does not typically encounter. Legs can move from one stable contact point to another without contact with unstable regions in between. Furthermore, intermittent, reciprocating actuation of legs by pneumatic or hydraulic cylinders is more common than would be for electrical drives which are inherently rotational.