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1 +BRAT Biped Autonomous Tutorial
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2 2  
24 +<div class="asm">
25 +
26 + <!-- Header -->
27 + <div style="padding: 0.5rem 0 1rem 0; display:flex; flex-wrap:wrap; gap:1.5rem; align-items:flex-start;">
28 + <div style="flex:1 1 300px;">
29 + <h1 class="asm">Biped BRAT Autonomous Tutorial</h1>
30 + <p><b>Updated December 20, 2011</b></p>
31 + <p><span class="asm-warning">Safety first!</span> Wear eye protection and never touch a powered robot!</p>
32 + <p><b>Hardware required:</b> Bot Board II, BASIC Atom Pro 28, Sharp GP2D12 sensor, Buffered 2-Axis Accelerometer (DE-11).</p>
33 + <p><b>Software &amp; downloads:</b></p>
34 + <ul style="padding-left:1.2rem; margin-top:0.25rem; line-height:1.8;">
35 + <li>BASIC Micro Studio</li>
36 + <li><a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/bratosf3.zip">BRAT Servo Offset Finder Program v3</a></li>
37 + <li><a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat1.zip">Autonomous Walk Code</a></li>
38 + <li><a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat2.zip">Autonomous GP2D12 Code</a> — Videos: <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/avoid01.mpg">Avoiding obstacle</a> · <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/break01.mpg">Taking a break</a> · <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/walkaway.mpg">Proximity beeps</a></li>
39 + <li><a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat3.zip">Autonomous 1-Axis Accelerometer Code</a> — Video: <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/getup01.mpg">Getting up front and back</a></li>
40 + <li><a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat4.zip">Autonomous 2-Axis Accelerometer Code</a> — Video: <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/getup02.mpg">Getting up front and side</a></li>
41 + </ul>
42 + </div>
43 + <div style="text-align:center; flex:0 1 280px;">
44 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/brat00.jpg" style="max-width:100%; border:1px solid #ccc; border-radius:4px;">
45 + <p style="font-size:12px; color:#666; margin-top:0.3rem;"><b>Biped BRAT.</b></p>
46 + </div>
47 + </div>
48 +
49 + <!-- Step 1 -->
50 + <div class="asm-step">
51 + <div class="asm-step-header">
52 + <div class="asm-step-name">Autonomous — Verify Servo Channel Connections</div>
53 + <div class="asm-step-num">Step 1 / 10</div>
54 + </div>
55 + <div class="asm-step-body">
56 + <div class="asm-step-text">
57 + <p>Make sure your servos are plugged into the appropriate channels per Table 1. Note: P9 is used by the speaker and cannot be used for a servo.</p>
58 + </div>
59 + <div class="asm-step-figure" style="flex: 0 1 auto;">
60 + <table class="ref-table" style="width:auto;">
61 + <tr><th>Bot Board I/O</th><th>Connection</th></tr>
62 + <tr><td>P4</td><td>Left Ankle</td></tr>
63 + <tr><td>P5</td><td>Left Knee</td></tr>
64 + <tr><td>P6</td><td>Left Hip</td></tr>
65 + <tr><td>P7</td><td>Right Ankle</td></tr>
66 + <tr><td>P8</td><td>Right Knee</td></tr>
67 + <tr><td>P10</td><td>Right Hip</td></tr>
68 + </table>
69 + <span style="margin-top:0.4rem;">Table 1.</span>
70 + </div>
71 + </div>
72 + </div>
73 +
74 + <!-- Step 2 -->
75 + <div class="asm-step">
76 + <div class="asm-step-header">
77 + <div class="asm-step-name">Autonomous — Configure Bot Board II Jumpers</div>
78 + <div class="asm-step-num">Step 2 / 10</div>
79 + </div>
80 + <div class="asm-step-body">
81 + <div class="asm-step-text">
82 + <p>Set the Bot Board II jumpers per Table 2. The VS to AX0 jumper enables the program to monitor servo battery voltage — when the battery is low the robot can beep a warning. Refer to Figure 2 for the jumper layout.</p>
83 + </div>
84 + <div class="asm-step-figure" style="flex: 0 1 auto;">
85 + <table class="ref-table" style="width:auto; margin-bottom:0.5rem;">
86 + <tr><th colspan="2">Bot Board II Jumper Settings (Table 2)</th></tr>
87 + <tr><td>Enable</td><td>A, B, and C buttons</td></tr>
88 + <tr><td>5V</td><td>I/O Group 0–3</td></tr>
89 + <tr><td>VS</td><td>I/O Groups 4–7 and 8–11</td></tr>
90 + <tr><td>Enable</td><td>SPKEN (Speaker Enable)</td></tr>
91 + <tr><td>Enable</td><td>VS (Servo Voltage) to AX0 (P16)</td></tr>
92 + </table>
93 + <span>Table 2.</span>
94 + </div>
95 + </div>
96 + <div class="asm-fullwidth">
97 + <p style="font-weight:bold; margin-bottom:0.4rem;">Figure 2 — Jumper diagram</p>
98 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/autobrat.gif" style="max-width:100%; border:1px solid #ccc; border-radius:4px;">
99 + </div>
100 + </div>
101 +
102 + <!-- Step 3 -->
103 + <div class="asm-step">
104 + <div class="asm-step-header">
105 + <div class="asm-step-name">Autonomous — Find Servo Offsets</div>
106 + <div class="asm-step-num">Step 3 / 10</div>
107 + </div>
108 + <div class="asm-step-body">
109 + <div class="asm-step-text">
110 + <p>Download and install BASIC Micro Studio. Download the <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/bratosf3.zip">BRAT Servo Offset Finder Program v3</a>, load it into the IDE, and program the Atom Pro. Then use the buttons to find offsets:</p>
111 + <ul style="margin-top:0.5rem; padding-left:1.2rem;">
112 + <li><b>A</b> — decrease servo offset by 5µs</li>
113 + <li><b>C</b> — increase servo offset by 5µs</li>
114 + <li><b>B</b> — change which servo is being adjusted, and save offsets (order shown in Figure 3)</li>
115 + </ul>
116 + <p>If the Speaker is enabled, pressing B plays a tone that rises in pitch as you cycle through servos, and drops to a longer tone when returning to Start.</p>
117 + </div>
118 + <div class="asm-step-figure">
119 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/bratosf3.jpg">
120 + <span>Figure 3 — Servo offset finder sequence.</span>
121 + </div>
122 + </div>
123 + </div>
124 +
125 + <!-- Step 4 -->
126 + <div class="asm-step">
127 + <div class="asm-step-header">
128 + <div class="asm-step-name">Autonomous — Calibrate Robot to Neutral Position</div>
129 + <div class="asm-step-num">Step 4 / 10</div>
130 + </div>
131 + <div class="asm-step-body">
132 + <div class="asm-step-text">
133 + <p>Place the robot as close to neutral as possible and turn it on. It should hold the neutral position resembling Figures 4-1 through 4-3. If any joint is off by more than 15°, remove the servo horn, rotate to align, and reattach. Use the A, B, and C buttons to fine-tune.</p>
134 + <p>Note: HS-422 hip servos may oscillate when the robot is lifted off the ground — this is normal and minimal when walking. Higher voltage makes oscillations worse. Higher-power servos (HS-475, HS-485, HS-645) do not exhibit this.</p>
135 + <p><span class="asm-warning">After adjusting all servos to match Figures 4-1 through 4-3, pressing B saves the offset values to the Atom Pro's EEPROM.</span></p>
136 + </div>
137 + <div class="asm-figures">
138 + <div class="asm-step-figure">
139 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/brat10.jpg">
140 + <span>Figure 4-1 (front view).</span>
141 + </div>
142 + <div class="asm-step-figure">
143 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/brat07.jpg">
144 + <span>Figure 4-2 (side view).</span>
145 + </div>
146 + <div class="asm-step-figure">
147 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/brat04.jpg">
148 + <span>Figure 4-3 (rear view).</span>
149 + </div>
150 + </div>
151 + </div>
152 + </div>
153 +
154 + <!-- Step 5 -->
155 + <div class="asm-step">
156 + <div class="asm-step-header">
157 + <div class="asm-step-name">Autonomous — Load Basic Walk Code</div>
158 + <div class="asm-step-num">Step 5 / 10</div>
159 + </div>
160 + <div class="asm-step-body">
161 + <div class="asm-step-text">
162 + <p>Download the <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat1.zip">BRAT Autonomous Walk Code</a>, load it into the IDE, and program your BRAT.</p>
163 + <p>The BRAT will now walk autonomously following this sequence: walk × 3, turn, long-stride × 2, kick, turn, stop. To customise behavior, modify the code between the labels "main" and "move", or create new sequences following the format below the "move" label.</p>
164 + </div>
165 + </div>
166 + </div>
167 +
168 + <!-- Step 6 -->
169 + <div class="asm-step">
170 + <div class="asm-step-header">
171 + <div class="asm-step-name">Autonomous — Mount &amp; Connect GP2D12 Sensor</div>
172 + <div class="asm-step-num">Step 6 / 10</div>
173 + </div>
174 + <div class="asm-step-body">
175 + <div class="asm-step-text">
176 + <p>Use double-sided tape to attach the GP2D12 sensor to the BRAT's head area, facing the front. Exact position is not critical. Plug the sensor into the channel shown in Table 6.</p>
177 + <table class="ref-table" style="width:auto; margin-top:0.5rem;">
178 + <tr><th>Bot Board I/O</th><th>Connection</th></tr>
179 + <tr><td>P19 (AX3)</td><td>GP2D12 Sensor</td></tr>
180 + </table>
181 + <p style="font-size:11px; color:#666; margin-top:0.3rem;">Table 6.</p>
182 + </div>
183 + <div class="asm-step-figure">
184 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/bratsens.jpg">
185 + <span>Figure 6 — GP2D12 sensor mounted.</span>
186 + </div>
187 + </div>
188 + </div>
189 +
190 + <!-- Step 7 -->
191 + <div class="asm-step">
192 + <div class="asm-step-header">
193 + <div class="asm-step-name">Autonomous — Load GP2D12 Obstacle Avoidance Code</div>
194 + <div class="asm-step-num">Step 7 / 10</div>
195 + </div>
196 + <div class="asm-step-body">
197 + <div class="asm-step-text">
198 + <p>Download the <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat2.zip">BRAT Autonomous GP2D12 Code</a>, load it into the IDE, and program your BRAT.</p>
199 + <p>The BRAT can now roam without bumping into obstacles. The sensor is read before each step. A short low beep means nothing is detected; the beep rises in pitch as objects get closer. At ~8" the robot backs up one step, turns left two steps, then continues. A looping counter periodically puts the robot into a resting position. LEDs illuminate based on the current command.</p>
200 + <p>Videos: <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/avoid01.mpg">Avoiding obstacle</a> · <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/break01.mpg">Taking a break</a> · <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/walkaway.mpg">Proximity beeps</a></p>
201 + </div>
202 + </div>
203 + </div>
204 +
205 + <!-- Step 8 -->
206 + <div class="asm-step">
207 + <div class="asm-step-header">
208 + <div class="asm-step-name">Autonomous — Mount &amp; Connect Accelerometer</div>
209 + <div class="asm-step-num">Step 8 / 10</div>
210 + </div>
211 + <div class="asm-step-body">
212 + <div class="asm-step-text">
213 + <p>Use double-sided tape to attach the accelerometer to the BRAT's head area. <span class="asm-warning">Axis orientation is critical — follow the orientation shown in Figure 8 exactly.</span> Plug the sensor into the channels shown in Table 8.</p>
214 + <table class="ref-table" style="width:auto; margin-top:0.5rem;">
215 + <tr><th>Bot Board I/O</th><th>Connection</th></tr>
216 + <tr><td>P17 (AX1)</td><td>Accelerometer Y Axis (front-to-back tilt)</td></tr>
217 + <tr><td>P18 (AX2)</td><td>Accelerometer X Axis (side-to-side tilt)</td></tr>
218 + </table>
219 + <p style="font-size:11px; color:#666; margin-top:0.3rem;">Table 8.</p>
220 + </div>
221 + <div class="asm-step-figure">
222 + <img src="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/bratacc.jpg">
223 + <span>Figure 8 — Accelerometer orientation.</span>
224 + </div>
225 + </div>
226 + </div>
227 +
228 + <!-- Step 9 -->
229 + <div class="asm-step">
230 + <div class="asm-step-header">
231 + <div class="asm-step-name">Autonomous — Load 1-Axis Accelerometer Code</div>
232 + <div class="asm-step-num">Step 9 / 10</div>
233 + </div>
234 + <div class="asm-step-body">
235 + <div class="asm-step-text">
236 + <p>Download the <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat3.zip">BRAT Autonomous 1-Axis Accelerometer Code</a>, load it into the IDE, and program your BRAT.</p>
237 + <p>This program uses only the Y Axis to detect front-to-back tilt — the BRAT can tell when it has fallen forward or backward and get back up. The X Axis will be incorporated in Step 10.</p>
238 + <p>Video: <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/getup01.mpg">Getting up front and back</a></p>
239 + </div>
240 + </div>
241 + </div>
242 +
243 + <!-- Step 10 -->
244 + <div class="asm-step">
245 + <div class="asm-step-header">
246 + <div class="asm-step-name">Autonomous — Load 2-Axis Accelerometer Code</div>
247 + <div class="asm-step-num">Step 10 / 10</div>
248 + </div>
249 + <div class="asm-step-body">
250 + <div class="asm-step-text">
251 + <p>Download the <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/abrat4.zip">BRAT Autonomous 2-Axis Accelerometer Code</a>, load it into the IDE, and program your BRAT.</p>
252 + <p>This version adds the X Axis for side-to-side tilt detection — if the BRAT falls onto its side it will roll over to get back up. It also includes an improved "get up from back" routine for robots with heavy cabling, and a "startled" behaviour: if the BRAT is resting and the GP2D12 suddenly detects an object, it will lean back and beep.</p>
253 + <p>Video: <a href="https://wiki.lynxmotion.com/info/wiki/lynxmotion/download/servo-erector-set-robots-kits/ses-v1-robots/ses-v1-bipeds/brat-biped-autonomous/WebHome/getup02.mpg">Getting up front and side</a></p>
254 + </div>
255 + </div>
256 + </div>
257 +
258 +</div>
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