2 The Basics

The section provides a brief introduction to the HUNTER 2.0 mobile robot platform, as shown in Figure 2.1 and 2.2

Designed as a complete intelligent module, HUNTER 2.0 combines inflatable rubber wheels with independent suspension as its power module, which, along with powerful DC brushless servo motor, enables the chassis of HUNTER 2.0 robot to flexibly move on different ground surfaces with high passing ability and ground adaptability. An emergency stop switch is mounted at the rear end of chassis body, which can shut down power of the robot immediately when the robot behaves abnormally. Water-proof connectors for DC power and communication interfaces are provided both on top and at the rear of the robot, which not only allow flexible connection between the robot and external components but also ensures necessary protection to the internal of the robot even under severe operating conditions.

2.1 Status indication

Users can identify the status of chassis body through the voltmeter, the beeper and lights mounted on HUNTER 2.0. For details, please refer to Table 2.1.

Table 2.1 Descriptions of Chassis Status

2.2 Instructions on electrical interfaces

2.2.1 Top electrical interface

HUNTER 2.0 provides two 4-pin aviation connectors and one DB9 (RS232) connector. (The current version can be used for upgrade of firmware but do not support for command).The position of the top aviation connector and DB9 interface is shown in Figure 2.3.

Figure 2.3 Schematic Diagram of HUNTER 2.0 Electrical Interface on Top

HUNTER 2.0 has each aviation extension interface respectively on top and at rear end which is configured with a set of power supply and a set of CAN communication interface. These interfaces can be used to supply power to extended devices and establish communication. The specific definitions of pins are shown in Figure 2.4.

It should be noted that, the extended power supply here is internally controlled, which means the power supply will be actively cut off once the battery voltage drops below the pre-specified threshold voltage. Therefore, users need to notice that HUNTER 2.0 platform will send a low voltage alarm before the threshold voltage is reached and also pay attention to battery recharging during use.

Figure 2.3 Description of Top Aviation Interface Pins

Top DB9 expansion interface pin definition.

Figure 2.5 Description of Top DB9 interface

2.2.2 Rear electrical interface

The extension interface at rear end is shown in Figure 2.6, where Q1 is the power display; Q2 is the switch of manual parking release; Q3 is the power switch; Q4 is the buzzer; Q5 is CAN and 24V power extension interface; Q6 is charging interface.

Figure 2.6 Rear View

Specific definitions for pins of Q5 are shown in Figure 2.7. The rear panel provides the same CAN communication interface and 24V power interface with the top one (two of them are internally inter-connected). The pin definitions are given in Figure 2.7.

Figure 2.7 Description of Rear Aviation Interface Pins

2.3 Remote control instructions

FS RC transmitter is provided (optional) for HUNTER 2.0. In this product, we use the left-hand-throttle design. Refer to Figure 2.8 for its definition and function.

Figure 2.8 Schematic Diagram of Buttons on FS RC transmitter

The function of the button is defined as: SWC and SWD are temporarily disabled. Among which SWA is the parking switch lever, turn to the top to release the parking mode, turn to bottom is the parking mode. (The remote control can be performed normally after the parking mode is released.) SWB for control mode selection, top position for command control and the middle position for remote control mode; S1 is the throttle button, which controls the forward and backward of HUNTER 2.0; S2 controls the steering of the front wheels, and POWER is the power button, press and hold it to turn on.

2.4 Instructions on control demands and movements

A reference coordinate system can be defined and fixed on the chassis body as shown in Figure 2.9 in accordance with ISO 8855.

Figure 2.9 Schematic Diagram of Reference Coordinate System for Chassis Body

As shown in Figure 2.9, the chassis body of HUNTER 2.0 is in parallel with X axis of the established reference coordinate system. In the remote control mode, push the remote control stick S1 forward to move in the positive X direction, push S1 backward to move in the negative X direction. When S1 is pushed to the maximum value, the movement speed in the positive X direction is the maximum, When pushed S1 to the minimum, the movement speed in the negative direction of the X direction is the maximum; the remote control stick S2 controls the steering of the front wheels of the car body, push S2 to the left, and the chassis turns to the left, pushing it to the maximum, and the steering angle is the largest, S2 Push to the right, the car will turn to the right, and push it to the maximum, at this time the right steering angle is the largest. In the control command mode, the positive value of the linear velocity means movement in the positive direction of the X axis, and the negative value of the linear velocity means movement in the negative direction of the X axis; the steering angle is the steering angle of the inner wheel.