Implementing real-time robotic systems using CHIMERA II

Stewart, David B.; Schmitz, D.E.; Khosla, Pradeep K.

doi:10.1109/icsyse.1990.203145

Cited by 12 publications

(10 citation statements)

References 9 publications

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“…We have implemented a state variable table mechanism (which we call svar) and integrated it with the Chimera II Real-Time Operating System [23]. Our target hardware architecture is a VMEbus-based [17] single-board computers, with multiple MC68030 processor boards.…”

Section: Methodsmentioning

confidence: 99%

“…We define a task as a separate thread of control within a multitasking operating system. The definition is consistent with that of the Chimera II Real-Time Operating System [23], and is also known as a thread in Mach and POSIX, and a lightweight process in some other operating systems. …”

mentioning

confidence: 90%

“…Simple mechanisms like local semaphores and only locking the CPU cannot be used, because they are only valid for single-processor applications. Multiprocessor mechanisms available include spin-locks [15], message passing, remote semaphores [23], and the multiprocessor priority ceiling protocol [20]. The message passing, remote semaphores, and multiprocessor priority ceiling protocol all require significant overhead, which is typically an order of magnitude greater than the data transfer itself.…”

Section: A Locking Mechanismmentioning

confidence: 99%

“…The message passing, remote semaphores, and multiprocessor priority ceiling protocol all require significant overhead, which is typically an order of magnitude greater than the data transfer itself. For example, the remote semaphores in Chimera II take a minimum of 44 µsec for the locking and unlocking operations, and as much as 200 µsec if the lock is not obtained on the first try and forces the task to block [23]. A typical transfer, on the other hand, may consist of 6 joint positions and 6 joint velocities, for a total of 12 transfers.…”

Section: A Locking Mechanismmentioning

confidence: 99%

“…Section III gives the architectural details of our control module integration. Section IV describes an efficient implementation of the state variable table mechanism, which has been integrated into the Chimera II Real-Time Operating System [23]. Finally, Section V summarizes the use of state variables for module integration in a reconfigurable system.…”

Section: Introductionmentioning

confidence: 99%

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Integration of real-time software modules for reconfigurable sensor-based control systems

Stewart

Volpe

Khosla³

Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems

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Abstract-In this paper we develop a framework for integrating real-time software modules that comprise a reconfigurable multisensor based system. Our framework is based on the proposed concept of a global database of state information through which realtime software modules exchange information. This methodology allows the development and integration of reusable software in a complex multiprocessing environment. A reconfigurable sensor-based control system consists of many software modules, each of which can be modelled using a simplified version of a port automaton. Our new state variable table mechanism can be used in both statically and dynamically reconfigurable systems, and it is completely processor independent. Individual modules may also be combined into larger modules to aid in building large systems, and to reduce bus and CPU utilization. An efficient implementation of the state variable table mechanism, which has been integrated into the Chimera II Real-Time Operating System, is also described. 1Keywords-reconfigurable sensor-based control systems, reusable software, real-time operating systems, interprocessor communication, spin-locks, real-time software modelling. I. INTRODUCTIONReal-time sensor based control systems are complex. In order to develop such systems, control strategies are needed to interpret and process sensing information for generating control signals. There has been considerable effort devoted to addressing this aspect of real-time control systems. However, even with robust control algorithms, a sophisticated software environment is necessary for efficient implementation into a robust system. The level of sophistication is even greater if this system is to be generalized so that it is reconfigurable and can perform more than a single task or application. Obviously, a real-time operating system (RTOS) is part of this software environment. However, it is also necessary to have a layer of abstraction between the RTOS and control algorithms that makes the implementation efficient, allows for easily expanding and/or changing the control strategies, and reduces development costs by incorporating the concept of reusable software. The development of this layer of abstraction is further motivated by the realization that real-time control systems are typically implemented in open-architecture multiprocessor environments. Several issues, such as configuring reusable modules to perform a job, allocating modules to processors, communicating between various modules, synchronizing modules running on separate processors, and determining correctness of a configuration, arise in this context. In this paper we develop a framework for integrating real-time software modules that comprise a reconfigurable multi-sensor based system. Our framework is based on the proposed concept of a global database of state information through which real-time software modules exchange information. This methodology allows the development and integration of reusable software in a complex multiprocessing environment. We def...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 90%

Section: A Locking Mechanismmentioning

confidence: 99%

Section: A Locking Mechanismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Integration of real-time software modules for reconfigurable sensor-based control systems

Stewart

Volpe

Khosla³

Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems

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The Design and Performance of a Real-Time CORBA Scheduling Service

Gill

Levine

Schmidt

2001

Challenges in Design and Implementation of Middlewares for Real-Time Systems

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Visual servoing in the task-function framework: A contour following task

Couvignou

Khosla

1995

J Intell Robot Syst

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Abstract.We describe an approach to contour following unknown objects using a handeye robotic system. Relevant and sufficient feature points providing optical flow data are extracted from the edges of the target object. The desired motion of the end-effector is computed with the objective of keeping thevisual features always at the same target location in the image plane. A cartesian PD controller is used to perform the desired motion by the robot's end-effector. To address the control issues, we take advantage of the unifying robot control theory stated in the literature as the task-function approach [21]. To validate our approach, we restricted our experiments to motionless objects positioned in a plane parallel to the image plane: three degrees of freedom (two of translation, one of rotation) are thus controlled.

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Implementing real-time robotic systems using CHIMERA II

Cited by 12 publications

References 9 publications

Integration of real-time software modules for reconfigurable sensor-based control systems

Integration of real-time software modules for reconfigurable sensor-based control systems

The Design and Performance of a Real-Time CORBA Scheduling Service

Visual servoing in the task-function framework: A contour following task

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