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WO-2026094138-A1 - DETERMINATION DEVICE

WO2026094138A1WO 2026094138 A1WO2026094138 A1WO 2026094138A1WO-2026094138-A1

Abstract

A determination device (30) for determining the number (N) of magnetic bodies (W) attracted to a magnet gripper (10) comprises: a coil (30c); a decision unit (74) that, on the basis of a first voltage (V1), which is the value of the coil voltage (Vc) at a time point (Tbe) at which a prescribed time (Tb) has elapsed since the start of excitation of the coil, decides on a second voltage (V2) lower than the first voltage; and a determination unit (78) that determines whether the number of the magnetic bodies is one on the basis of the time required (Td) for the value of the coil voltage to reach the second voltage after the coil has been excited, degaussed, and then excited again.

Inventors

  • KATSUMATA KOICHI
  • OSHIMA YUTA

Assignees

  • SMC株式会社

Dates

Publication Date
20260507
Application Date
20241029

Claims (7)

  1. A determination device (30) for determining the number (N) of magnetic materials (W) attracted to a magnetic gripper (10), Coil (30c), A voltage application circuit (32) capable of applying DC voltages (Vd, Vdd) and alternating voltages (Vd, Vda) to the coil using the power supply voltage (Vs) of a DC power supply (Ps), A control unit (70) controls the voltage application circuit to apply the DC voltage to the coil, thereby exciting the coil, and controls the voltage application circuit to apply the alternating voltage to the coil, thereby demagnetizing the coil. A detection circuit (34) for detecting the coil voltage (Vc) generated between the ends of the coil, A determination unit (74) determines a second voltage (V2) that is smaller than the first voltage, based on a first voltage (V1) which is the value of the coil voltage at a predetermined time (Tbe) after a predetermined time (Tb) has elapsed since the excitation of the coil was started by applying the DC voltage to the coil, A timing unit (76) measures the time required (Td) from when the coil is energized and then demagnetized by the control unit until the coil voltage reaches the second voltage, A determination unit (78) determines whether or not the number of magnetic materials is one, based on the time required, A determination device equipped with the following features.
  2. A determination device according to claim 1, When the control unit acquires a trigger input signal, it controls the voltage application circuit to apply the DC voltage to the coil, thereby starting the excitation of the coil. The control unit demagnetizes the coil after the predetermined time has elapsed since the excitation of the coil began. After the control unit demagnetizes the coil, when the coil voltage reaches the second voltage due to the re-energizing of the coil, the control unit controls the voltage application circuit to apply the alternating voltage to the coil, thereby demagnetizing the coil again. A determination device in which no voltage is applied to the coil from the time the control unit demagnetizes the coil again until the trigger input signal is acquired again.
  3. A determination device according to claim 1, The voltage application circuit is composed of an H-bridge including a plurality of switches (SW1, SW2, SW3, SW4), The control unit is a determination device that controls the voltage application circuit by switching between a plurality of switches.
  4. A determination device according to any one of claims 1 to 3, The system further includes a storage unit (62) that stores in advance time thresholds (T1, T2) used to determine the number of magnetic materials, The determination unit is a determination device that determines whether or not the number of magnetic materials is one by comparing the required time with the time threshold.
  5. A determination device according to claim 4, The storage unit stores a plurality of time thresholds in advance, The determination unit is a determination device that determines whether the number of magnetic materials is one, zero, or two or more by comparing the required time with a plurality of time thresholds.
  6. A determination device according to claim 4, The storage unit stores a plurality of time thresholds in advance, The determination unit is a determination device that determines the number of magnetic materials by comparing the required time with a plurality of time thresholds.
  7. A determination device according to any one of claims 1 to 3, The determination device further comprises a notification device (42) that notifies the determination result of the determination unit regarding whether or not the number of magnetic materials is one.

Description

Judgment device This disclosure relates to a determination device. Japanese Patent Publication No. 8-219707 discloses a device for detecting the attraction of two workpieces to an electromagnetic chuck. The device determines whether one workpiece is being attracted to the chuck using the output of a coil. There is room to improve the accuracy of determining whether or not only one magnetic object is attached to the magnetic gripper. This disclosure aims to solve the problems described above. An aspect of this disclosure is a determination device for determining the number of magnetic materials attracted to a magnetic gripper, comprising: a coil; a voltage application circuit capable of applying a DC voltage and an alternating voltage to the coil using the power supply voltage of a DC power supply; a control unit that controls the voltage application circuit to apply the DC voltage to the coil to excite the coil and controls the voltage application circuit to apply the alternating voltage to the coil to demagnetize the coil; a detection circuit for detecting the coil voltage generated between the ends of the coil; a determination unit that determines a second voltage smaller than the first voltage based on a first voltage, which is the value of the coil voltage at a predetermined time after the excitation of the coil by applying the DC voltage to the coil begins; a timing unit that measures the time required from when the coil is excited again after being excited and demagnetized by the control unit until the value of the coil voltage reaches the second voltage; and a determination unit that determines whether the number of magnetic materials is one based on the required time. According to this disclosure, the accuracy of determining whether or not one magnetic material is attached to the magnetic gripper can be improved. Figure 1A shows the state where the number of magnetic objects attached to the magnetic gripper is 0. Figure 1B shows the state where the number of magnetic objects attached to the magnetic gripper is 1. Figure 1C shows the state where the number of magnetic objects attached to the magnetic gripper is 2.Figure 2 illustrates a determination device that determines the number of magnetic materials attracted to a magnetic gripper.Figure 3 illustrates the temporal changes in the voltage applied to the coil of a magnetic gripper, the temporal changes in the current flowing through the coil, and the temporal changes in the detected coil voltage.Figure 4A illustrates the change in coil voltage detected when the number of magnetic objects attached to the magnetic gripper is 0. Figure 4B illustrates the change in coil voltage detected when the number of magnetic objects attached to the magnetic gripper is 1. Figure 4C illustrates the change in coil voltage detected when the number of magnetic objects attached to the magnetic gripper is 2.Figure 5 shows an example of determining the number of magnetic materials attracted to a magnetic gripper.Figure 6 is a flowchart illustrating the procedure for determining the number of magnetic objects attached to the magnetic gripper. Robots sometimes supply workpieces to industrial equipment. For example, a robot might supply a steel plate to a press machine. If the supplied workpiece is a magnetic material like a steel plate, a magnetic gripper may be used as the robot's end effector. A magnetic gripper has a magnet, such as a permanent magnet or electromagnet. The magnetic force of the magnet in the magnetic gripper attracts the magnetic workpiece to the gripper. Figure 1A shows the state where the number of magnetic materials W attached to the magnetic gripper 10 is zero. The magnetic gripper 10 is attached to the robot 20. The magnetic gripper 10 has a magnet. The robot 20 brings the magnetic gripper 10 close to the top magnetic material W of a stack of multiple magnetic materials W. When one magnetic material W is attracted to the magnetic gripper 10 by the magnetic force of the magnet on the magnetic gripper 10, the robot 20 can supply that magnetic material W to the industrial equipment. In the example shown in Figure 1A, even though the magnetic gripper 10, which generates magnetic force, is brought close to the magnetic material W, the magnetic material W is not attracted to the magnetic gripper 10. In this case, the robot 20 cannot supply the magnetic material W to the industrial equipment. Therefore, the state in which the number of magnetic materials W attracted to the magnetic gripper 10 is zero is undesirable. Figure 1B shows the state where one magnetic material W is attracted to the magnetic gripper 10. In the example shown in Figure 1B, as a result of bringing the magnetic gripper 10, which is generating magnetic force, closer to the magnetic material W, one magnetic material W is attracted to the magnetic gripper 10. In this case, the robot 20 can supply the magnetic material W to industrial equipment. Here, we will explain the problems that may