Target-seeking control method and system for mobile robots

A computer software product, comprising a non-transitory medium readable by a processor, the non-transitory medium having stored thereon a set of instructions for performing a target-seeking control method for a mobile robot, the set of instructions including;

• (a) a first sequence of instructions which, when executed by the processor, causes said processor to initialize the robot, its environment, and a target point in a subjective environment (SE) that corresponds to the target in an objective environment (OE);
• (b) a second sequence of instructions which, when executed by the processor, causes said processor to set an iteration number for relaxation of a scalar potential field in the OE defined by operation of a sensor on the robot;
• (c) a third sequence of instructions which, when executed by the processor, causes said processor to set a margin of safety in discrete location surrounding obstacles in the OE located by the robot's sensor;
• (d) a fourth sequence of instructions which, when executed by the processor, causes said processor to initialize a discrete representation of the SE;
• (e) a fifth sequence of instructions which, when executed by the processor, causes said processor to initialize a representation of the scalar potential field corresponding to the discrete representation of the SE;
• (f) a sixth sequence of instructions which, when executed by the processor, causes said processor to perform a full field relaxation of the scalar potential field based on the iteration number, wherein a strength of the scalar potential field is reduced, the discrete SE representation and the scalar potential field representation being updated accordingly;
• (g) a seventh sequence of instructions which, when executed by the processor, causes said processor to process feedback signals applied to the robot;
• (h) an eighth sequence of instructions which, when executed by the processor, causes said processor to obtain a guidance signal from a guidance system of the robot;
• (i) a ninth sequence of instructions which, when executed by the processor, causes said processor to update variables of the robot;
• (j) a tenth sequence of instructions which, when executed by the processor, causes said processor to generate a control signal for the robot;
• (k) an eleventh sequence of instructions which, when executed by the processor, causes said processor to apply the control signal to the robot;
• and
• (l) a twelfth sequence of instructions which, when executed by the processor, causes said processor to apply a stop signal to the robot when the robot has stopped due to the target being reached.

A target-seeking control system for a mobile robot, comprising:

• a tangential speed computation block having a tangential speed computation input, and outputting a tangential speed command, vc;
• a desired angular speed computation block having desired angular speed computation inputs and outputting a desired angular speed, ωc;
• a wheel speed control block connected to the tangential speed computation block and the desired angular speed computation block, the wheel speed control block accepting as inputs the tangential speed command, vc and the desired angular speed, ωc and outputting independent wheel speed commands to wheels of the robot;
• a speed computation block computing the robot's speed,
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• in SE (subjective environment);
• an integrator block connected to the speed computation block and computing the robot's position,
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• in SE based on the robot's SE speed,
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• ;
• a guidance command block accepting as inputs the robots environment, the target's position, and the robot's position,
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• ,
• the guidance command block outputting guidance signals, Gx, Gy;
• means for using the guidance signals Gx, Gy and the robot's speed
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• to form signals applied to the desired angular speed computation inputs;
• means for using the target position and robot's position
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• to form a signal applied to the tangential speed computation input;
• means for initializing the robot, its environment, and the target point in a subjective environment (SE) that corresponds to the target in an objective environment (OE);
• means for setting an iteration number for relaxation of a scalar potential field in the OE defined by operation of a sensor on the robot;
• means for setting a margin of safety in discrete location surrounding obstacles in the OE located by the robot's sensor;
• means for initializing a discrete representation of the SE;
• means for initializing a representation of the scalar potential field corresponding to the discrete representation of the SE;
• means for performing a full field relaxation of the scalar potential field based on the iteration number, whereby the scalar potential field's strength is reduced, the discrete SE representation and the scalar potential field representation being updated accordingly;
• and
• means for applying a stop signal to the robot when the robot has stopped due to the target being reached.