The abstract introduced develops voluntarily half independent remote control migration robot assembly system’s software and hardware design proposal. Take TI Corporation TMS320LF2407The model DSP chip as the robot car controller core, the key elaboration system localization module, the image gathering module and the wireless data waits on loses the module and so on, and gives PC machine and between the DSP data passes on the siberian elm agreement as well as the experimental result.
Key word digital signal processor (DSP) motion robot GPRS image transmission
Introduction
The robot technology fuses the Ding machinery, the electricity, the sensor, the computer, the artificial intelligence and so on many discipline theories and the technology, is now many front domain technology complex compound. The migration robot mainly uses to some dangerous and the unknown region carries on the exploration, for example is outside the exploration the star surface, carries on the detonation land mine and so on to need to use the migration robot. Because half independent remote control migration robot has strong characteristics and so on energy, good controllability, in the industry and agriculture, the national defense and so on each domain has the widespread application prospect. In half independent remote control moves in robot’s control operation, needs person’s participation. Therefore needs to have a man-machine interaction channel, transmits person’s instruction to the robot execution, simultaneously the robot may also the scene information feedback which gathers deceive the human. This article based on the motion robot principle, designed two rounds actuated half independent motion robot’s hardware system, elaborated in detail with realized based on the GPRS technology’s long-distance controller’s design.
1 remote control migration robot assembly system composition
The system whole by the remote control platform, the wireless transmission network as well as the local robot car three majorities is composed. DSP is the local robot car’s control core. TI male
Department’s TMS320LF2407A chip has the improvement Harvard structure system, has used merits and so on assembly line technology, and has used the high performance static state CMOS/technology, reduces 3.3V the chip running voltage, reduced the chip power loss greatly. Its CPU has pours the processing speed very high, the frequency may achieve 40 MHz, the complex algorithm can implement in the systems control. In addition, it also integrated 32 KB to dodge saves, 16 pulse-duration modulation (PWM) channel, 1 CAN module, as well as 1 supervelocity 500 ns 10 modulus switch (ADC) and so on function formidable peripheral devices.
The overall system take F2407A as controller’s core, expanded the robot main body man-machine connection (the LCD demonstration and pressed key) the module, the environment photograph module, the actuation electrical machinery module, the electro-optical encoder feedback module as well as the GPRS man-machine interaction module and so on. Control system structure diagram as shown in Figure 1.
1.1 robot car’s localization module
The robot localization module mainly by the electrical machinery and the driving circuit, the mechanical drive system and the electro-optical encoder and so on is composed. Between the driving gear and the electro-optical encoder uses the gear drive, the velocity ratio is i, the electro-optical encoder’s resolution is N (i.e. encoder revolves every time one week output pulse number), driving gear’s radius is r, then the encoder outputs a pulse every time, the corresponding wheel the distance which passes through in the ground is
The motor control uses pulse-duration modulation (PWM) the velocity modulation way, and by DSP the bringing orthogonal code pulse (QEP) electric circuit gathering electro-optic encoder’s feedback information, carries on the closed loop PID control to the electrical machinery. Using the QEP electric circuit capture electro-optic encoder’s feedback signal may the reduced program establishment, simultaneously use the PID control principle, may increase system’s control precision and the stability.
Motor-driven schematic diagram as shown in Figure 2. Actuates the main chip is the L293B, L293B direct current machine actuates the chip permission voltage range in 4.5~36V, in has four heavy push-pulls (dual H bridge integration power amplifier electric circuit) the driving circuit, two channels may provide l A to the respective electrical machinery the drive current, if and chip overheated, the chip can the automatic cutout, the safeguard system not damage. When A to, B to for high level, then electrical machinery A, the B electric current flows to 6 feet and 11 feet separately by 3 feet flows to 14 feet, electrical machinery clockwise; Otherwise, when A to, B to for low level, the electrical machinery electric current flows to 3 feet and 14 feet separately by 6 feet flows to 11 feet, the electrical machinery reverse. This time, might use PWM to control on the chip the electrical machinery to enable foot’s make-and-break time recently to carry on the velocity modulation to the electrical machinery, F2407The DSP chip supports the PWM output, therefore might to actuate the electrical machinery to carry on the velocity modulation very conveniently.
Because DSP chip bringing has the orthogonal encoder capture module, therefore this part of circuit design is quite simple. The electro-optical encoder outputs the orthogonal signal impulse stabilizes after the complementer, enters DSP the chip the QEP electric circuit to catch by CPU and to distinguish, will distinguish after again the information takes the PID control algorithm the feedback input.
1.2 LCD demonstrations and photograph module
The LCD display module and the photograph module’s data format is 8, with monolithic integrated circuit and so on micro controller’s connection nimble simple. The photograph module may output after the compression the JPEG form image, therefore the data quantity is small, lightened the controller data processing burden, simultaneously reduced GPRS to transmit image time, timeliness is better. F2407A has provided the rich I/O connection, may very conveniently carries on the data with the I/O mouth to the LCD module and the photograph module read-in and reads. Because the LCD module’s data is reads, but photographs the module the data is the read-out, therefore may the time sharing multiplying identical group I/O mouth, but will not have the conflict. After the design, controls these two modules with the different pilot wire to enable the end separately to realize the time sharing multiplying, uses DSP I/OPB0~I/OPB7 to take their data interface.
2 GPRS wireless image transmission
GPRS (General Packet Radio Selvice) is one kind based on the package of wireless communication service. It is one kind of new GSM data traffic, may give the mobile subscriber to provide the packet radio data to meet the human to serve. GPRS is mainly provides one kind of connection to the mobile subscriber and between the far-end data net, thus provides high speed wireless IP and the wireless X.25 service to the mobile subscriber.
The GPRS data transmission’s merit is:
◇ the transmission speed is high;
◇ real-time online;
◇ according to current capacity charge;
◇ is not away from the influence far and near;
◇ registers quickly.
2.1 GPRS network way
In this system, realizes the information two-way transmission using the GPRS mobile communication network. The robot car passes to the long-distance monitoring platform the data mainly to include the scene pictorial information and the car current localization information; The long-distance monitoring platform passes to the car is mainly the command information.
The GPRS image gathering module by gathers the terminal, the DSP periphery connection, the GPRS transceiver, the PC machine connection and the monitoring center software is composed. Image data after gathering, by the DSP serial port transmission for the GPRS transceiver 1, transmits by transceiver l the image data through the GPRS wireless network, again image data transmission which 2 will receive from the GPRS transceiver for the PC machine serial port, then monitors the central software from the PC machine serial port read data and demonstrated finally in monitors on the central contact surface, completes the scene the real-time monitoring. GPRS network way structure drawing as shown in Figure 3.
2.2 image data gathering program flow diagram
The image gathering process transmits two major parts including the DSP serial port correspondence initialization and the image data. The monitoring center issues the gathering image instruction, after the GPRS module the signaling for the DSP serial port, starts the DSP serial port the interrupt servicing, gathers the camera image data, and by way of the GPRS module the data transmission for the long-distance monitoring center, completes an image the gathering cycle. Image data gathering procedure flow as shown in Figure 4.
The DSP chip’s software design supports the C language, the assembly language as well as both mix programming, because this system involves to image data processing, electrical machinery PID control algorithm realization with the LCD demonstration and so on, the procedure is numerous, the programming work load is big, therefore with the mix programming’s method, may unify the C language and the assembly language merit well, compiles the efficiency high procedure code.
2.3 data transmission protocol
The data transmission protocol divides into two parts, a part is the corpse C machine transmission for DSP the control command, another part is the DSP transmission for the PC machine feedback information. The data transmission form uses the data packet form, must therefore to each time need to transmit the data carries on pack processing, the concrete data packet type is as follows;
And data packet’s various units definition is as follows:
◇ the outset flag bit is a byte, fixture 0×00;
◇ the control word is a byte, the value scope is 0×0l~0xff, the concrete representative’s data type sees 2.3.1 and 2.3.2;
◇ the data length unit is two bytes, the value scope is 0×0001~0xffff, low byte before, high byte, indicated that treats the transmission data the byte count;
◇ waits the transmission data unit the byte count not to decide, the content by the data content decision which transmits specifically;
◇ the data check unit is a byte, the value to treat the transmission data each byte different or obtains;
◇ finished the flag bit is a byte, the fixture is 0×01.
2.3.1 PC machine to DSP data transmission protocol
The PC machine transmission for the microprocessor DSP data type including the gathering image instruction, assigns the robot to walk the type and the reply feedback instruction and so on. After DSP receives each kind of instruction which PC machine sends out, reads the data content, then data content each byte different or, the value which different or obtains with the verification code which receives carries on again the comparison, if equal, is correct to the PC feedback data receive, then changes over to the corresponding instruction the interrupt service; If not equal, then makes a mistake to the PC machine feedback data receive, the application transmits the instruction. Various instructions definition like
Table 1 arranges in order.
2.3.2 DSP to PC machine data transmission protocol
DSP transmits to the PC machine data type mainly includes the robot current position feedback data, the image data as well as the DSP reply feedback instruction and so on. After PC machine receive data, after carrying on the verification the treating processes and the previous section introduction DSP receive data treating processes is the same. The robot car in walks in the process, will transmit once in a while own current position data to PC machine, will realize the real-time way track, when after simultaneously DSP will receive the gathering image instruction which the superior machine will send out, will carry on image gathering, then the image data transmission which will gather for PC machine to carry on image display, has realized the robot car environment information real-time monitoring. Concrete instruction definition like table 2 arrange in order.
3 experimental results
The monitoring center software uses the Delphi higher order language establishment. In a fence inputs Ol in “the control command” (Ol to represent gathering image instruction), the click “the transmission”, monitors the contact surface “the image monitoring” the fence to be able afterward to demonstrate the camera gathers long-distance environmental information.
When experiment, camera’s resolution adjustment for 320×240, two GPRS transceivers in was distanced separately about 4 m room both sides, Figure 5 has demonstrated the experimental result. The experimental result indicated: Has achieved the anticipated effect based on the GPRS mobile communication network and the DSP technology’s half independent motion robot remote system. Simultaneously also discovered in the experiment that GPRS transmission data’s timeliness is limited, although the transmission speed reaches as high as 171 kb/s theoretically, but in fact receives many kinds of factors the influences, the actual speed is low, transmits a 3K JPEG form image probably to need 3O~60s the time. Therefore, how further enhances system’s timeliness is the biggest challenge which this system faces.
