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Anatomy of a Robot Part 10

Tham khảo tài liệu 'anatomy of a robot part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 166 CHAPTER SEVEN FIGURE 7-1 Battery voltage varies during a discharge cycle. This is especially true if no power supply circuitry exists and the robot is running off the battery directly. Internal resistance Batteries will all have different internal resistances. This behaves much like a resistor in series with the battery. As the battery ages this resistance may change. When a motor or other heavy load places a sudden demand on the battery for current the voltage of the battery will change quickly. Make sure the rest of the robot s control circuitry and sensitive instrumentation can take the sudden voltage transient on the power supply. Lifetime Don t forget that the ability of batteries to store energy will change over time. Many types of batteries with different internal chemistry will lose their capability to store power as the battery ages. Within the battery chemicals gases and metals migrate or slowly corrode so they are no longer able to fully contribute to energy storage. Make sure the robot s circuitry will be able to function just as well when the robot and its batteries reach old age see Figure 7-2 . Power Requirements If we are trying to power a robot using just the battery as our power supply we need to limit the number of different voltages that will be needed within the robot. This may mean that all the electrical components must be selected so they can work off the same voltage. This becomes quite a challenge when we try to pick motors sensors and computers that all have similar requirements for voltage. So what voltage should we try for High voltage for example is not a good choice for running computers or most sensors. Motors To complicate things further low voltage does not work well to move motors. We can use very low voltage drop Field Effect Transistors FETs to control the motor ENERGY CONTROL AND SOFTWARE 167 FIGURE 7-2 An elderly robot toy windings and keep the efficiency up. Semiconductor companies sell chips specifically designed to .