Abstract:
An embodiment of the invention provides a control method of a cleaning robot. The method includes steps of moving the cleaning robot according to a first direction; keeping moving the cleaning robot according to the first direction when a light detector of the cleaning robot detects a light beam; moving the cleaning robot for a predetermined distance and then stopping the cleaning robot when the light detector does not detect the light beam; and moving the cleaning robot in a second direction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/599,690 filed Feb. 16, 2012, the entirety of which is incorporated by reference light generating devices Application claims priority of Taiwan Patent Application No. 101139410, filed on Oct. 25, 2012, the entirety of which is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a cleaning robot, and more particularly, to a cleaning robot with a non-omnidirectional light detector. 
         [0004]    2. Description of the Related Art 
         [0005]    A variety of movable robots, which generally include a driving means, a sensor and a travel controller, and perform many useful functions while autonomously operating, have been developed. For example, a cleaning robot for the home, is a cleaning device that sucks dust and dirt from the floor of a room while autonomously moving around the room without user manipulation. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    An embodiment of the invention provides a control method of a cleaning robot. The method comprises steps of moving the cleaning robot according to a first direction; keeping moving the cleaning robot according to the first direction when a light detector of the cleaning robot detects a light beam; moving the cleaning robot for a predetermined distance and then stopping the cleaning robot when the light detector does not detect the light beam; and moving the cleaning robot in a second direction. 
         [0007]    Another embodiment of the invention provides a cleaning robot comprising a controller and a light detector. The controller controls the cleaning robot to move in a first direction. The light detector is coupled to the controller and detects a light beam. When detecting the light beam output by a light generating device, the light detector transmits a first trigger signal to the controller. When the light detector does not detect the light beam, the light detector transmits a second trigger signal to the controller. The controller controls the cleaning robot to stop after moving a distance and leaves a restricted area labeled by the light beam in a second direction. 
         [0008]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0010]      FIG. 1  is a schematic diagram of a light generating device and a cleaning robot according to an embodiment of the invention. 
           [0011]      FIG. 2   a  is a top view of an embodiment of a non-omnidirectional light detector according to the invention. 
           [0012]      FIG. 2   b  is a flat view of the non-omnidirectional light detector of  FIG. 2   a.    
           [0013]      FIGS. 2   c  and  2   d  are schematic diagrams for estimating an incident angle of a light beam by using the proposed non-omnidirectional light detector according to the invention. 
           [0014]      FIG. 2   e  is a schematic diagram of another embodiment of a non-omnidirectional light detector according to the invention. 
           [0015]      FIG. 3   a  and  FIG. 3   b  show a schematic of a control method of a cleaning robot according to an embodiment of the invention. 
           [0016]      FIG. 4  is a flowchart of a control method for a cleaning robot according to an embodiment of the invention. 
           [0017]      FIG. 5  shows a schematic of a control method of a cleaning robot according to another embodiment of the invention. 
           [0018]      FIG. 6  is a functional block diagram of an embodiment of a cleaning robot according to the invention. 
           [0019]      FIG. 7  is a schematic diagram of a logic level of the pin GPIO_ 1  of  FIG. 6 . 
           [0020]      FIG. 8  is a flowchart of a control method for a cleaning robot according to another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0022]      FIG. 1  is a schematic diagram of a light generating device and a cleaning robot according to an embodiment of the invention. The light generating device  12  outputs a light beam  15  to label a restricted area that the cleaning robot  11  cannot enter. The cleaning robot  11  comprises a non-omnidirectional light detector  13  having a rib (or called mask)  14 , where the rib  14  produces a shadowed area on the non-omnidirectional light detector  13  by a predetermined angle and the range of the predetermined angle is from 30 degrees to 90 degrees. 
         [0023]    The rib  14  may be fixed on the surface of the non-omnidirectional light detector  13  or movable along the non-omnidirectional light detector  13 . The rib  14  can be spun in 360 degrees along the surface of the non-omnidirectional light detector  13 . In this embodiment, the term, non-omni, is a functional description to describe that the rib  14  causes an area on the surface of the non-omnidirectional light detector  13  and the non-omnidirectional light detector  13  cannot not detect light therein or light to not directly reach that area. 
         [0024]    Thus, the non-omnidirectional light detector  13  can be implemented in two ways. The first implementation is to combine an omni-light detector with a rib  14  and the rib  14  is fixed on a specific position of the surface of the omni-light detector. The non-omnidirectional light detector  13  is disposed on a plate that can be spun by a motor. Thus, the purpose of spinning of the non-omnidirectional light detector  13  can be achieved. When the non-omnidirectional light detector  13  detects the light beam, an incident angle of the light beam  15  can be determined by spinning the non-omnidirectional light detector  13 . 
         [0025]    Another implementation of the non-omnidirectional light detector  13  is implemented by telescoping a mask kit on an omni-light detector, wherein the omni light detector cannot be spun and the masking kit is movable along a predetermined track around the omni light detector. The mask kit is spun by a motor. When the non-omnidirectional light detector  13  detects the light beam  15 , the mask kit is spun to determine the incident angle of the light beam  15 . 
         [0026]    Reference can be made to  FIGS. 2   a  to  2   e  for the detailed description of the non-omnidirectional light detector  13 . 
         [0027]      FIG. 2   a  is a top view of an embodiment of a non-omnidirectional light detector according to the invention. The mask  22  is formed by an opaque material and is adhered to a part of sensing area of an omni light detector  21 . The mask  22  forms a sensing dead zone with an angle θ on the omni light detector  21 . 
         [0028]    Please refer to  FIG. 2   b .  FIG. 2   b  is a flat view of the non-omnidirectional light detector of  FIG. 2   a . In  FIG. 2   b , the omni light detector  21  is fixed on a base  23 . The base  23  can be driven and spun by a motor or a step motor. A controller of the cleaning robot outputs a control signal to spin the base  23 . Although the typical type of omni light detector  21  can receive light from any direction, the omni light detector  21  cannot determined the direction that the light comes from and the cleaning robot cannot know the position of a light generating device or charging station. With the help of the mask  22 , the light direction can be determined. 
         [0029]    When the omni light detector  21  detects a light beam, the base  23  is set to be spun for 360 degrees in a clockwise direction or a counter clockwise direction. When the omni light detector  21  cannot detect the light beam, a controller of the cleaning robot calculates a spin angle of the base  23 , wherein the spin angle ranges from 0 degree to (360-θ) degrees. The controller then determines the direction of the light beam according to a spin direction of the base  23 , the spin angle and the angle θ. Reference can be made to the descriptions related to  FIG. 2   c  and  FIG. 2   d  a more detailed description for estimating an incident angle of a light beam. 
         [0030]      FIGS. 2   c  and  2   d  are schematic diagrams for estimating an incident angle of a light beam by using the proposed non-omnidirectional light detector according to the invention. In  FIG. 2   c , the initial position of the mask  22  is at P 1 . When the non-omnidirectional light detector  25  detects a light beam  24 , the non-omnidirectional light detector  25  is spun in a predetermined direction. In this embodiment, the predetermined direction is a counter clockwise direction. In  FIG. 2   d , when the non-omnidirectional light detector  25  does not detect the light beam  24 , the non-omnidirectional light detector  25  stops spinning. The controller of the cleaning robot determines a spin angle Φ of the non-omnidirectional light detector  25  and estimates the direction of the light beam  24  according to the spin angle Φ and the initial position P 1 . 
         [0031]    In another embodiment, the non-omnidirectional light detector  25  is driven by a motor, and the motor transmits a spin signal to the controller for estimating the spin angle Φ. In another embodiment, the non-omnidirectional light detector  25  is driven by a step motor. The step motor is spun according to numbers of received impulse signals. The controller therefore estimates the spin angle Φ according to the number of impulse signals and a step angle of the step motor. 
         [0032]    In another embodiment, the non-omnidirectional light detector  25  is fixed on a base device with a gear disposed under the base device, wherein meshes of the gear are driven by the motor. In another embodiment, the non-omnidirectional light detector  25  is driven by the motor via a timing belt. 
         [0033]      FIG. 2   e  is a schematic diagram of another embodiment of a non-omnidirectional light detector according to the invention. The non-omnidirectional light detector  26  comprises an omni light detector  27 , a base  28  and a vertical extension part  29  formed on the base  28 . The vertical extension part  29  is formed by an opaque material and forms a dead zone area on the surface of the omni light detector  27 . When the light beam is toward to the dead zone area, the omni light detector  27  cannot detect the light beam. The base  28  is spun by a motor to detect a light direction. The omni light detector  27  is not physically connected to the base  28  and the omni light detector  27  is not spun when the base is spun by the motor. Reference can be made to the descriptions related to  FIGS. 2   c  and  2   d  for the light direction detection operation of the non-omnidirectional light detector  26 . 
         [0034]      FIG. 3   a  and  FIG. 3   b  show a schematic of a control method of a cleaning robot according to an embodiment of the invention. The light generating device  33  outputs a light beam to label a restricted area that the cleaning robot  31  cannot enter. The light beam comprises a first boundary b 1  and a second boundary b 2 . At time T 1 , the cleaning robot  31  moves along a predetermined route. At time T 2 , the light detector  32  detects a first boundary b 1  of the light beam output by the light generating device  33 . The cleaning robot  31  keeps moving along the predetermined route. In this embodiment, the light detector is a non-omnidirectional light detector or an omnidirectional light detector. 
         [0035]    At time T 3 , the light detector  32  does not detect the light beam output by the light generating device  33 . The cleaning robot  31  keeps moving for a distance d and then is spun 180 degrees. At time T 4  of  FIG. 3   b , the light detector  32  detects a first boundary b 1  of the light beam output by the light generating device  33 . At time T 5 , the light detector  32  does not detect the light beam output by the light generating device  33 . A controller of the cleaning robot  31  determines whether the cleaning robot  31  has left the restricted area according to the detection results of the light detector  32  at time T 4  and time T 5 . 
         [0036]      FIG. 4  is a flowchart of a control method for a cleaning robot according to an embodiment of the invention. In the step S 41 , the cleaning robot moves according to a preset route. In the step S 42 , a controller of a light detector determines whether a light beam from the light generating device is detected by the light detector of the cleaning robot. If the light detector detects the light beam from the light generating device, step S 43  is executed. In this embodiment, the light detector is an omnidirectional light detector or a non-omnidirectional light detector, such as shown in  FIG. 2   a - FIG. 2   e.    
         [0037]    In the step S 43 , the controller of the light detector transmits a first trigger signal to a controller of the cleaning robot. In the step S 44 , the controller of the light detector determines whether the light detector detects the light beam from the light generating device. If yes, step S 44  is still executed. If not, step S 45  is executed. In the step S 45 , the controller of the light detector transmits a second trigger to the controller of the cleaning robot. In the step S 46 , the controller of the cleaning robot executes a corresponding procedure and the cleaning robot therefore move away from the restricted area labeled by the light beam output by the light generating device. 
         [0038]    In this embodiment, the first trigger signal is a rising edge-triggered signal and the second trigger signal is a falling edge-triggered signal. 
         [0039]      FIG. 5  shows a schematic of a control method of a cleaning robot according to another embodiment of the invention. The light generating device  53  outputs a light beam to label a restricted area that the cleaning robot  51  cannot enter. The light beam comprises a first boundary b 1  and a second boundary b 2 . At time T 1 , the cleaning robot  51  moves along a predetermined route. At time T 2 , the non-omnidirectional light detector  52  detects a first boundary b 1  of the light beam output by the light generating device  53 . The cleaning robot  51  does not stop immediately but stops after the cleaning robot  51  keeps moving for a distance d. 
         [0040]    At time T 2 , when the non-omnidirectional light detector  52  detects the light beam output by the light generating device  53 , a controller of the cleaning robot  51  receives a first trigger signal. The controller of the cleaning robot  51  therefore knows that the cleaning robot  51  is near the restricted area and the controller can execute some operations, such as slowing down the moving speed of the cleaning robot  51 , pre-activating a light detection 
         [0041]    At time T 3 , the non-omnidirectional light detector  52  does not detect the light beam output by the light generating device  53 . It means that the cleaning robot  51  has entered the restricted area. The controller of the cleaning robot  51  receives a second trigger signal and the controller prepares to stop the cleaning robot  51  according to the second trigger signal. In this embodiment, when the controller receives the second trigger signal, the controller stops the cleaning robot  51  after a predetermined duration t. In another embodiment, when the controller receives the second trigger signal, the controller stops the cleaning robot  51  after N clock cycles or N sampling times. 
         [0042]    The controller determines the distance d or the duration t according to a moving speed, a moving mode or a breaking time. 
         [0043]    At time T 3 , the non-omnidirectional light detector  52  is spun to determine the position of the light generating device  53 . Then, the controller of the cleaning robot  51  determines how the cleaning robot  51  leaves the light beam from the light generating device  53 . The controller of the cleaning robot  51  controls the cleaning robot  51  to spin 180 degrees and leaves along the original route or in another direction. 
         [0044]    Assuming the controller of the cleaning robot  51  determines that the area I is not cleaned yet, the cleaning robot  51  is spun 180 degrees and leaves along the original route. When the cleaning robot  51  leaves the second boundary b 2  of the light beam from the light generating device  53 , the cleaning robot  51  moves to the light generating device  53  along the second boundary b 2  and cleans the area that the cleaning robot  51  had passed. 
         [0045]    In another embodiment, if the controller of the cleaning robot  51  determines that the area I had been cleaned, and the area II is not cleaned yet, the controller of the cleaning robot  51  determines a shortest path to the area II and determines a first direction according to the shortest path. Then, the cleaning robot  51  moves in the first direction. In other words, the controller of the cleaning robot  51  controls the cleaning robot  51  to move to the un-cleaned area according to the cleaned area and the previous moving track. 
         [0046]      FIG. 6  is a functional block diagram of an embodiment of a cleaning robot according to the invention. The controller  61  executes the program  62  and controls a detector  63  coupled to a general purpose input/output (GPIO) pin GPIO_ 1  of the controller  61 . The logic level of the pin GPIO_ 1  is preset at a first logic level. When the detector  63  detects the light beam output by a light generating device, the logic state of the pin GPIO_ 1  is changed from the first logic level to the second logic level. When the detector  63  does not detect the light beam output by a light generating device, the logic state of the pin GPIO_ 1  is changed from the second logic level to the first logic level. Thus, when the controller  61  receives a square wave signal via the pin GPIO_ 1 , it means that the cleaning robot has entered the restricted area. 
         [0047]      FIG. 7  is a schematic diagram of a logic level of the pin GPIO_ 1  of  FIG. 6 . Before time t 1 , the pin GPIO_ 1  maintains at the preset logic low level (L). At time t 1 , the light detector detects the light beam from the light generating device and the light detector pulls the logic level of the pin GPIO_ 1  to a logic high level (H). During the duration between time t 1  and time t 2 , the logic level of the pin GPIO_ 1  maintains at the logic high level (H) because the cleaning robot is moving at the area covered by the light beam from the light generating device. 
         [0048]    At time t 2 , the cleaning robot leaves the area covered by the light beam from the light generating device and the light detector does not detect the light beam from the light generating device. The light detector pulls the logic level of the pin GPIO_ 1  down to a logic low level (L). During the duration between time t 2  and time t 3 , the cleaning robot moves a distance and leaves the restricted area in a first direction. The cleaning robot passes the area covered by the light beam from the light generating device again. 
         [0049]    At time t 3 , the light detector detects the light beam from the light generating device again, and the light detector pulls the logic level of the pin GPIO_ 1  to a logic high level (H). During the duration between time t 3  and time t 4 , the logic level of the pin GPIO_ 1  maintains at the logic high level (H) because the cleaning robot is moving at the area covered by the light beam from the light generating device. 
         [0050]    According to the above paragraphs, when the controller  61  detects the first square wave signal, such as the square wave signal between time t 1  and time t 2 , the cleaning robot has entered the restricted area. When the controller  61  detects the second square wave signal, such as the square wave signal between time t 3  and time t 4 , the cleaning robot has left the restricted area. Thus, the controller  61  controls the cleaning robot to leave the restricted area according to the program  62  and determines whether the cleaning robot has left the restricted area according to the number of the detected square wave signals. 
         [0051]      FIG. 8  is a flowchart of a control method for a cleaning robot according to another embodiment of the invention. In the step S 801 , the cleaning robot moves according to a preset route. In the step S 802 , a controller of a light detector determines whether a light beam is detected by the light detector of the cleaning robot. If not, step S 801  is executed. If the light detector detects the light beam from the light generating device, step S 803  is executed to confirm whether the light beam is output by the light generating device. If the light beam is not output by the light generating device, step S 801  is executed. If the light beam is output by the light generating device, step S 804  is then executed. 
         [0052]    In the step S 804 , the controller of the light detector transmits a first trigger signal to a controller of the cleaning robot, and the cleaning robot still moves along the preset route. In the step S 805 , the controller of the light detector or the controller of the cleaning robot determines whether the light detector detects the light beam. If yes, step S 804  is executed. If light detector does not detect the light beam, the step S 806  is executed. 
         [0053]    In the step S 806 , the controller of the light detector transmits a second trigger signal to the controller of the cleaning robot. Then, in the step S 807 , the controller of the cleaning robot determines a leaving direction and the cleaning robot left from the restricted area according to the leaving direction. 
         [0054]    In the step S 808 , the controller of the light detector determines whether the light detector detects the light beam. If the light detector does not detect the light beam, the procedure returns to the step S 807 . If the light detector detects the light beam, step S 809  is executed. In the step S 809 , the light detector transmits a third trigger signal to a controller of the cleaning robot, and the cleaning robot keeps moving. 
         [0055]    In the step S 810 , the controller of the light detector or the controller of the cleaning robot determines whether the light detector detects the light beam. If yes, step S 809  is executed and the cleaning robot keeps moving along the preset route. If light detector does not detect the light beam, the step S 811  is executed. 
         [0056]    In the step S 811 , the controller of the light detector transmits a fourth trigger signal to the controller of the cleaning robot. When the controller of the cleaning robot receives the third trigger signal and the fourth trigger signal, the controller of the cleaning robot confirms that the cleaning robot has left the restricted area. In other words, the third trigger signal and the fourth trigger signal can be referenced for determining whether the cleaning robot has left the restricted area. 
         [0057]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.