Multi-joint underwater robot having complex movement functions of walking and swimming and underwater exploration system using same
Disclosed is an underwater exploration system using a multi-joint underwater robot having a novel complex movement concept in which the multi-joint underwater robot moves through walking or swimming with multi-joint legs closely to a seafloor, differently from a conventional underwater robot to obtain a thrust through a propeller scheme. The underwater exploration system includes the multi-joint underwater robot having the complex movement function according, a depressor, and a mother ship to store data of an underwater state transmitted from the multi-joint underwater robot and to monitor and control a movement direction of the multi-joint underwater robot. The depressor is connected to the mother ship through a primary cable, the multi-joint underwater robot is connected to the depressor through a second cable, and resistance force of the primary cable is applied to the depressor without being transmitted to the multi-joint underwater robot.
1. A multi-joint underwater robot having a complex movement function, the multi-joint underwater robot comprising:
a streamlined body;
multi-joint walking legs mounted at left and right sides and a front side of the body, each of the walking legs having multiple joints;
a control unit mounted in the body to control a walking state and a swimming state through the multi-joint walking legs;
a walking leg driving unit controlled by the control unit and generating a driving signal to drive the multi-joint walking legs;
a sensing unit mounted in the body to sense a posture of the body and contact of the body with an external object;
a buoyancy sensing unit mounted in the body to sense buoyancy of the body; and
a communication unit to transceive wired and wireless signals with an external device,
wherein the sensing unit comprises:
a force/moment sensor mounted between the body and the legs of the multi-joint underwater robot;
a landing force sensor mounted in an end portion of the legs; and
a moment sensor mounted at two front legs among the multi-joint walking legs of the multi-joint underwater robot to sense landing of the front legs, and
wherein each leg of the multi-joint walking legs has a link structure of four joints, and the two front legs of the multi-joint walking legs have link structures of six joints, the joints constituting the two front legs are utilized when the two front legs are used for robot arms, which perform roll, pitch, and yaw rotation motions about X, Y, and Z axes, respectively, and
wherein a joint mechanism of the multi-joint walking legs comprises:
joint driving motors including frameless BLDC motors;
harmonic drive reducers minimizing backlashes of the multi-joints and obtaining proper deceleration ratios;
electric encoders, mounted at the harmonic drive reducers output side, obtaining absolute angles of the multi-joints from the harmonic drive reducers and providing the absolute angles; and
joint limit sensors, mounted at the multi-joints, comprising magnetic proximity switches sensing feedbacks of the multi-joints.
2. The multi-joint underwater robot of claim 1 , wherein an ultrasonic camera is mounted at a front surface of the body.
3. The multi-joint underwater robot of claim 1 , wherein the sensing unit comprises a posture sensor and a motion measuring sensor.
4. The multi-joint underwater robot of claim 1 , wherein the sensing unit comprises an underwater location tracking device.
5. The multi-joint underwater robot of claim 1 , further comprising a photographing unit mounted at a front surface of the body to photograph an underwater image,
wherein the photographing unit comprises an underwater camera having a pan/tilting function, and a lighting device.
6. The multi-joint underwater robot of claim 1 , wherein the communication unit comprises an optical communication modem.
7. The multi-joint underwater robot of claim 1 , wherein the communication unit is connected to a depressor through a secondary cable including an optical fiber and a power line.
8. The multi-joint underwater robot of claim 1 , wherein the body includes a light-weight and high-strength complex fiber.
9. The multi-joint underwater robot of claim 1 , wherein the buoyancy sensing unit variably adjusts a weight of the multi-joint underwater robot in a range of −10 kg to +10 kg, and
the two front legs among the multi-joint walking legs have grippers such that the front legs selectively have a robot arm function.
10. An underwater exploration system using a multi-joint underwater robot having a complex movement function, the underwater exploration system comprising:
the multi-joint underwater robot having the complex movement function comprising:
a streamlined body;
multi-joint walking legs mounted at left and right sides and a front side of the body, each of the multi-joint walking legs having multiple joints;
a control unit mounted in the body to control a walking state and a swimming state through the multi-joint walking legs;
a walking leg driving unit controlled by the control unit and generating a driving signal to drive the multi-joint walking legs;
a sensing unit mounted in the body to sense a posture of the body and contact of the body with an external object, the sensing unit comprising:
a force/moment sensor mounted between the body and the legs of the multi-joint underwater robot;
a landing force sensor mounted in an end portion of the leg; and
a moment sensor mounted at two front legs of the multi-joint underwater robot to sense landing of the front legs;
a buoyancy sensing unit mounted in the body to sense buoyancy of the body; and
a communication unit to transceive wired and wireless signals with an external device, wherein each leg of the multi-joint walking legs has a link structure of four joints, and the two front legs of the multi-joint walking legs have link structures of six joints, the joints constituting the two front legs are utilized when the two front legs are used for robot arms, which perform roll, pitch, and yaw rotation motions about X, Y, and Z axes, respectively,
wherein a joint mechanism of the multi-joint walking legs comprises:
joint driving motors including frameless BLDC motors;
harmonic drive reducers minimizing backlashes of the multi-joints and obtaining proper deceleration ratios;
electric encoders, mounted at the harmonic drive reducers output side, obtaining absolute angles of the multi-joints from the harmonic drive reducers and providing the absolute angles; and
joint limit sensors, mounted at the multi-joints, comprising magnetic proximity switches sensing feedbacks of the multi-joints;
a depressor; and
a mother ship to store data of an underwater state transmitted from the multi-joint underwater robot and to monitor and control a movement direction of the multi-joint underwater robot,
wherein the depressor is connected to the mother ship through a primary cable,
the multi-joint underwater robot is connected to the depressor through a second cable, and
resistance force of the primary cable is applied to the depressor without being transmitted to the multi-joint underwater robot.
11. The underwater exploration system of claim 10 , wherein the multi-joint underwater robot further comprises:
a first switching hub to switch a plurality of signals;
an optical fiber converter to convert a received signal into an optical signal;
a computer connected to the first switching hub to process input and output signals;
RS232, RS485, USB, and/or CAN devices connected to the computer;
a second switching hub having one terminal connected to the first switching hub and an opposite terminal connected to a plurality of network cameras;
a video encoder having one terminal connected to the first switching hub and an opposite terminal connected to a plurality of analog cameras;
a forward scanning sonar serving as a forward looking sonar, connected to the first switching hub, photographing an image through a forward scanning work, and transmitting the image; and
an ultrasonic camera connected to the first switching hub and photographing and transmitting a forward image.
12. The underwater exploration system of claim 10 , wherein the depressor comprises:
a switching hub switching a plurality of signals;
an optical fiber converter connected to the switching hub to convert a signal, which is received through the switching hub, into an optical signal and to transmit the signal to the mother ship;
a computer processing input and output signals and having one terminal connected to an RS232 and an opposite terminal connected to the switching hub;
a video encoder having one terminal connected to a plurality of analog cameras and an opposite terminal connected to the switching hub; and
a plurality of network cameras connected to the switching hub.
13. The underwater exploration system of claim 10 , wherein the mother ship comprises first and second optical fiber converters having one terminal connected to a plurality of computers and an opposite terminal to transmit an optical signal, and
the first and second optical fiber converters are connected to an optical fiber converter of the multi-joint underwater robot and an optical fiber converter of the depressor, respectively.