Through funding from the US Army-Tank-Automotive and Armaments Command's (TACOM) Intelligent Mobility Program, Utah State University's (USU) Center for Self-Organizing and Intelligent Systems (CSOIS) has developed the T-series of omni-directional robots based on the USU omni-directional vehicle (ODV) technology. The ODV provides independent computer control of steering and drive in a single wheel assembly. By putting multiple omni-directional (OD) wheels on a chassis, a vehicle is capable of uncoupled translational and rotational motion. Previous robots in the series, the T1, T2, T3, ODIS, ODIS-T, and ODIS-S have all used OD wheels based on electric motors. The T4 weighs approximately 1400 lbs and features a 4-wheel drive wheel configuration. Each wheel assembly consists of a hydraulic drive motor and a hydraulic steering motor. A gasoline engine is used to power both the hydraulic and electrical systems. The paper presents an overview of the mechanical design of the vehicle as well as potential uses of this technology in fielded systems.
Previous research has produced the T-series of omni- directional (ODV) robots, which are characterized by their use of smart wheel technology. In this paper we describe the design, implementation, and performance of the first use of ODV technology in a complete robotic system for a practical, real-world application. The system discussed is called ODIS, short for Omni-Directional Inspection System. ODIS is a man- portable mobile robotic system that can be used for autonomous or semi-autonomous inspection under vehicles in a parking area. The ODIS system can be deployed to travel through a parking area, systematically determining when a vehicle is in a parking stall and then carrying out a sweep under the vehicle, while sending streaming video back to a control station. ODIS uses three ODV wheels designed with a belt-driven steering mechanism to facilitate the low profile needed to fit underneath most vehicles. Its vetronics capabilities include eight different processors and a sensor array that includes a range-finding laser, sonar and IR sensors, and a color video camera. The ODIS planning and control architecture is characterized by a unique coupling between the vehicle-level path-tracking control system and a novel sensor-based feedback system for intelligent behavior generation. Real-life examples of ODIS's performance show the effectiveness of the system.
A six-wheeled autonomous omni-directional vehicle (ODV) called T3 has been developed at Utah State University's (USU) Center for Self-Organizing and Intelligent Systems (CSOIS). This paper focuses on T3's ability to climb stairs using its unique configuration of 6 independently driven and steered wheels and active suspension height control. The ability of T3, or any similar vehicle, to climb stairs is greatly dependent on the chassis orientation relative to the stairs. Stability criteria is developed for any vehicle dimensions and orientation, on any staircase. All possible yaw and pitch angles on various staircases are evaluated to find vehicle orientations that will allow T3 to climb with the largest margin of stability. Different controller types are investigated for controlling vertical wheel movement with the objective of keeping all wheels in contact with the stairs, providing smooth load transfer between loaded and unloaded wheels, and maintaining optimum chassis pitch and roll angles. A controller is presented that uses feedback from wheel loading, vertical wheel position, and chassis orientation sensors. The implementation of the controller is described, and T3's stair climbing performance is presented and evaluated.
In response to ultra-high maneuverability vehicle requirements, Utah State University (USU) has developed an autonomous vehicle with unique mobility and maneuverability capabilities. This paper describes a study of the mobility of the USU T2 Omni-Directional Vehicle (ODV). The T2 vehicle is a mid-scale (625 kg), second-generation ODV mobile robot with six independently driven and steered wheel assemblies. The six wheel, independent steering system is capable of unlimited steering rotation, presenting a unique solution to enhanced vehicle mobility requirements. This mobility study focuses on energy consumption in three basic experiments, comparing two modes of steering: Ackerman and ODV. The experiments are all performed on the same vehicle without any physical changes to the vehicle itself, providing a direct comparison these two steering methodologies. A computer simulation of the T2 mechanical and control system dynamics is described.
To enhance the mobility of the USU T-class of vehicles, the T3 vehicle has been developed that incorporates Z-axis motion of the drive wheel modules. Moving the wheels up and down provides the ability to pitch and roll the vehicle chassis and move the vehicle center of gravity to change the force distribution on the individual drive wheels. The omni- directional capability of the vehicle provides the capability to align the vehicle with the slope gradient that maximizes the vehicle stability. This paper shows that by pitching the vehicle into the slope, that the uphill traction limit of the vehicle can be increased by about 10 degree(s). Future research efforts concerning stair climbing, step negotiation, and obstacle field navigation are also discussed.
Beginning in FY98 and continuing in FY99, the Center for Self-Organizing and Intelligent Systems (CSOIS) at Utah State University (USU) has been funded by the US Army Tank-Automotive and Armaments Command's (TACOM) Intelligent Mobility Program to develop and demonstrate enhanced mobility concepts for unmanned ground vehicles (UGV). The long-range goal of the program is to develop and demonstrate enabling technologies that allow lightweight robotic and semiautonomous ground vehicles to achieve on-road and off-road mobility and survivability similar to current manned, wheeled, and tracked military vehicles, with a focus on small-scale to mid-scale vehicles. This paper describes the design concept and the performance of the T-series of robotic vehicles resulting from the TACOM Intelligent Mobility funding at USU (the T1, T2 and T3). USU-TACOM intelligent mobility concepts discussed in the paper include: (1) inherent mobility capability improvements, achieve through the unique concept of USU's omni-directional vehicle (ODV) steering design, which features six independently-controlled smart wheels; (2) intelligent mobility control, enhanced through intelligent coordination and control of each of the six wheels in the ODV vehicles; (3) global mobility control, enhanced through USU optimal multi-agent mission and mobility planning system; and (4) future mobility capability and control.
In response to ultra-high maneuverability vehicle requirements, Utah State University (USU) has developed an autonomous vehicle with unique mobility and maneuverability capabilities. This paper describes the mechanical design of the USU T2 Omni-Directional Vehicle (ODV). The T2 vehicle is a second- generation ODV and weighs 1350 lb with six independently driven and steered wheel assemblies. The six wheel, independent steering system is capable of infinite rotation, presenting a unique solution to enhanced vehicle mobility requirements. Mechanical design of the wheel drive motors and the performance characteristics of the drive system are detailed. The steering and suspension system is discussed and the design issues associated with these systems are detailed. The vehicle system architecture, vetronics architecture, control system architecture, and kinematic-based control law development are described.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.