Abstract: An adaptive, discrete-time sliding mode controller (SMC) is disclosed which detects and adapts to gain variations in the controlled plant. The overall control effort is generated by combining a linear control effort with a discrete-time sliding mode control effort generated by switching between gains in order to drive the system's phase states toward a sliding line trajectory. A sliding mode variable &sgr;k defines the position of the system phase states relative to the sliding line. The SMC controller is designed such that the sliding mode variable &sgr;k crosses the sliding line and changes sign at every sample interval. For the nominal plant gain, the SMC controller is also designed such that the magnitude of the sliding mode variable &sgr;k+1=−&sgr;k will remain constant (&sgr;k+1=−&sgr;k) and substantially constrained to |&sgr;k|=&Dgr;/(1+&lgr;) where &Dgr; and &lgr; are predetermined design constants.

Abstract: An information processing system comprises a plurality of systems (1, 3, 4, 6) communicating through a transmission path (2) and performing a processing base on their own function. One of the plurality of systems acts as as an supervising system having a supervising function. The supervising system (1, 4) sets a goal for each of the plurality of systems, collects the processing result on each system and evaluates the processing result; and on the basis of the processing result, the supervising system sets a new goal for each system considering a goal of the entire system comprising said plurality of systems.

Abstract: A multi-purpose controller for variables which closely controls such variables to set point by making sequential corrections to the level of input to the system of the variable based on: system response time, relationship of controller output to the variable, deviation of the variable from set point, and change in system load as determined by change in error and change in system input. The controller has a self tuning capability and can provide generation of the set point according to a set of variable parameters. It can be configured as a stand alone controller, as an intelligent Input/Output device for another intelligent device, or be resident in another intelligent device such as a programmable controller, computer or other microprocessor based device.

Abstract: A deadband control assistant, operating as part of a control system, eliminates oscillation of a controlled process output around a desired setpoint. The deadband control defines a deadband range, and steady-state-stabilization-time for the process being controlled. When the process output is within the deadband range and oscillation around the setpoint occurs for the steady-state-stabilization-time, the error is set to zero. The control signal may simultaneously be set, or may settle to a fixed value. The deadband control assistant thus allows the process output to stabilize as close as possible to the desired setpoint. Normal process control may resume once the process output strays outside the deadband range.

Abstract: A control device and its method by which interference between a blade (10) of a bulldozer and a vehicle body can be prevented even when a pitch back angle of the blade (10) is made large and a tilt speed is increased to greatly change a tilt angle. Therefore, the device comprises left and right detecting means (20a, 20b, 23a, 23b) for detecting an amount of tilt of the blade (10), left and right tilt limiting valves (37, 38) connected to operating units (35a, 35b) of first and second directional control valves (35, 36), and a controller (50) outputting a command to the left and right tilt limiting valves (37, 38) so as to stop a tilting action of the blade (10) when a difference between amounts of tilt detected by the left and right detecting means (20a, 20b, 23a, 23b) reaches a predetermined limit value.

Abstract: A method and apparatus for optimizing digital processing in a computer system is accomplished when at least one of a plurality of digital processing operations (i.e., a set of programming instructions) receives a user request. The user request may include a request to execute the set of programming instructions and may further include data which would be operated upon by the digital processing operation. Upon receiving the request, the addressed digital processing operation (DPO) informs a controlling digital processing operation of the request, such that the controlling DPO may determine whether the addressed digital processing operation is of a first type. A first type digital processing operation is one that may produce a hang-up, an error, or is not optimized when executed alone or when executed in parallel with another digital processing operation.