Difference between revisions of "Modern Robotics Errata"

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[https://docs.google.com/forms/d/1iZ_3LsWR1iuPJmRsUQsa2ehZj6p-qKQfx8NRKaTlIuE/edit '''Please click here to report any corrections for the book. (Please make sure you are using the May 3, 2017, online version of the book, or the hardcover book published by Cambridge University Press.)''']
The book version posted October 9, 2016 can be considered a beta version. Corrections and clarifications are being collected before a new version is generated, likely in late November. Until that next version, errata are being posted here. Only significant issues are being posted here, to avoid cluttering the page. Small typos are not recorded here.


Errata below are for [[Modern_Robotics|the hardcover book published by Cambridge University Press and the preprint version of the book posted on May 3, 2017]]. Thanks to everyone who provided corrections to earlier versions!
* Chapter 4

** p135: "The of a robot" should be "The forward kinematics of a robot" (latex indexing mistake)

== Significant corrections ==

=== Chapter 3 ===

* In the caption of Figure 3.3, it should read <math>\hat{\text{x}}_{\text{b}} = (1/2, \sqrt{3}/2)</math> and <math>\hat{\text{y}}_{\text{b}} = (-\sqrt{3}/2, 1/2)</math>.
* There is a typo in the final matrix, <math>T_{ce}</math>. The term <math>130/\sqrt{2}</math> should be <math>160/\sqrt{2}</math>. (Also, there is no need to use <math>T_{ad}</math> in this example.)
* In the displayed equation just after Equation (3.76), the left-hand side should be <math>[\mathcal{V}_s]</math> (the brackets are missing).
* Exercise 3.16(i) asks for "the <math>\{q,\hat{s},h\}</math> representation" but it should say "a <math>\{q,\hat{s},h\}</math> representation" since <math>q</math> is not unique.

=== Chapter 4 ===

* Example 4.1, last row of the table (screw axis for joint 3): The linear component <math>v_i</math> should be <math>(0, -L_2, 0)</math> (the <math>-</math> sign is missing).

=== Chapter 5 ===

* Equation (5.7): The the first two terms on the right-hand side of the equation should be <math>J_{s1} \dot{\theta}_1 + J_{s2}(\theta) \dot{\theta}_2</math>.

* Exercise 5.2(b): The wrench applied by the last link, expressed in the {s} frame, is 5 N in the <math>\hat{\text{y}}_{\text{s}}</math> direction, with zeros in all other components. (The wording seems to imply that the force is through the tip of the last link, which is incorrect.)

* Exercise 5.16 and Figure 5.26: The robot is referred to as PRRRRR, but it is PRPRRR.

=== Chapter 6 ===

* Chapter 6.3, first line after Eq (6.7): the matrices <math>T_{sd}^{-1} \dot{T}_{sd}</math> and <math>\dot{T}_{sd} T_{sd}^{-1}</math> are referred to as twists, but these are the se(3) matrix representations of the twists.

=== Chapter 8 ===

* In Equation (8.14), <math>\mathcal{K}(\theta)</math> should be replaced by <math>\mathcal{K}(\theta,\dot{\theta})</math>.

* Figure 8.5 says the volume of the rectangular parallelepiped is <math>abc</math> but it should be <math>hlw</math>.

* End of first sentence after Eq (8.26) in Section 8.2.1 should read "columns of <math>R_{bc}</math> correspond to the eigenvectors of <math>\mathcal{I}_b</math>." (The word "eigenvalues" should be replaced by "eigenvectors.")

* Caption of Figure 8.10: The operating region is light gray and the continuous operating region is dark gray.

* Exercise 8.6(a): The expression <math>\text{ad}_{J_i}(J_j)</math> has the indices switched; the correct expression is <math>\text{ad}_{J_j}(J_i)</math>.

* Exercise 8.7: The expression should be written:
<math>
\dot{M} = -\mathcal{A}^{\rm T} \mathcal{L}^{\rm T} \mathcal{W}^{\rm T} [\mbox{ad}_{\mathcal{A} \dot{\theta}}]^{\rm T} \mathcal{L}^{\rm T} \mathcal{GLA} -
\mathcal{A}^{\rm T} \mathcal{L}^{\rm T} \mathcal{GL} [\mbox{ad}_{\mathcal{A} \dot{\theta}}] \mathcal{WLA}
</math>

=== Chapter 10 ===

* Equation (10.4) should read <math> u = F(q) - B \dot{q}</math> (the plus sign in the book should be a minus sign).

=== Chapter 11 ===

* In the displayed equation after Equation (11.18), the vector <math>X_e(t)</math> is a six-vector. The bottom three elements are written correctly, but the top three elements, an angular velocity, are written instead in their 3x3 <math>so(3)</math> form.

* In Equation (11.33), the right-hand side should be zero (<math>c = 0</math>).

* Figure 11.24, the Robonaut 2 series elastic actuator, 4th sentence of the caption: The words "outer" and "inner" should be switched, so the new sentence reads "The inner ring of hole mounts connects to the harmonic gearhead output, and the outer ring of hole mounts is the output of the SEA, connecting to the next link."

=== Appendix C ===

* Section C.3, Equation (C.5): All instances of <math>\phi_{i-1}</math> should be replaced by <math>\phi_i</math>.

* In Equation (C.12), two instances of <math>M_{i-1}</math> should be replaced by <math>M_i</math>.

== Minor typos, etc., no danger of misunderstanding ==

=== Chapter 1 ===

* (online version only) Description of Chapter 6: "jont positions" should be "joint positions."

=== Chapter 2 ===

* Chapter 2.2.2, Example 2.3: "Substituting" is misspelled.

=== Chapter 5 ===

* Figure 5.15(b): The circular arrow indicating the rotation of joint 3 is slightly misplaced.

* Exercise 5.25: This problem instructs you to use the space Jacobian, so you should use it for the manipulability ellipsoids in this problem (even though it is generally preferred to use the body Jacobian for manipulability ellipsoids).

=== Chapter 6 ===

* (online version only) Figure 6.7: <math>\theta_0</math> should be <math>\theta^0</math> (five times) and <math>\theta_1</math> should be <math>\theta^1</math> (one time).

=== Chapter 7 ===

* (online version only) Last line of first paragraph of Chapter 7.1: "valuees" should be "values."
* Just below caption for Figure 7.8: There is an extraneous dot.

=== Chapter 8 ===

* (online version only) Chapter 8.1.1, last paragraph: <math>\dot{\theta}_1</math> is improperly typeset.

=== Chapter 12 ===

* Caption of Figure 12.14, second-to-last sentence: "rotation if possible" should be "rotation is possible."

== A partial list of errata contributors ==

Thanks to the following people who provided corrections, starting from the preliminary version of the book posted in October, 2016:

H. Andy Nam, Eric Lee, Yuchen Rao, Chainatee Tanakulrongson, Mengjiao Hong, Kevin Cheng, Jens Lundell, Elton Cheng, Michael Young, Jarvis Schultz, Logan Springgate, Sofya Akhmametyeva, Aykut Onol, Josh Holcomb, Yue Chen, Mark Shi, AJ Ibraheem, Yalun Wen, Seongjae Jeong, Josh Mehling, Felix Wang, Drew Warren, Chris Miller, Clemens Eppner, Zack Woodruff, Jian Shi, Jixiang Zhang, Shachar Liberman, Will Wu, Dirk Boysen, Awe Wang

<!--
Other updates and corrections can be found in the google drive folder.

Other minor things, not worth mentioning:

Could give an operation to convert so(3) and se(3) to their vector reps, e.g., ]log T_{ab}[ or vec(log T_{ab}) .

In figs showing blocks sliding in channels in chapter 2 (e.g., exercises), some show arrows to show the sliding motion possibility, others do not. Could be confusing, i.e., if arrows are missing maybe motion isn't possible.

Eq (5.4): transpose should be roman, not italic

After Eq (5.26), in text, transpose should be roman

near end of chap 7.2.1: the inverse transpose should be roman

Chapters 5.1.6 and 6.3 use term "(inverse) velocity kinematics" while 7.2 uses the term "differential kinematics"

Eq (8.21) and equation before: inverse transposes are italic, not roman.

Eq (8.81): no reason to make tau a function of time, since it is not done for the others.

Chapter 8.6: several instances of inverse transpose being italic, not roman.

A few paragraphs after eq (13.31), it says the absolute value of v_d should not be zero. Should just say that v_d should not be zero.
-->

Revision as of 23:01, 7 November 2018

Please click here to report any corrections for the book. (Please make sure you are using the May 3, 2017, online version of the book, or the hardcover book published by Cambridge University Press.)

Errata below are for the hardcover book published by Cambridge University Press and the preprint version of the book posted on May 3, 2017. Thanks to everyone who provided corrections to earlier versions!


Significant corrections

Chapter 3

  • In the caption of Figure 3.3, it should read and .
  • There is a typo in the final matrix, . The term should be . (Also, there is no need to use in this example.)
  • In the displayed equation just after Equation (3.76), the left-hand side should be (the brackets are missing).
  • Exercise 3.16(i) asks for "the representation" but it should say "a representation" since is not unique.

Chapter 4

  • Example 4.1, last row of the table (screw axis for joint 3): The linear component should be (the sign is missing).

Chapter 5

  • Equation (5.7): The the first two terms on the right-hand side of the equation should be .
  • Exercise 5.2(b): The wrench applied by the last link, expressed in the {s} frame, is 5 N in the direction, with zeros in all other components. (The wording seems to imply that the force is through the tip of the last link, which is incorrect.)
  • Exercise 5.16 and Figure 5.26: The robot is referred to as PRRRRR, but it is PRPRRR.

Chapter 6

  • Chapter 6.3, first line after Eq (6.7): the matrices and are referred to as twists, but these are the se(3) matrix representations of the twists.

Chapter 8

  • In Equation (8.14), should be replaced by .
  • Figure 8.5 says the volume of the rectangular parallelepiped is but it should be .
  • End of first sentence after Eq (8.26) in Section 8.2.1 should read "columns of correspond to the eigenvectors of ." (The word "eigenvalues" should be replaced by "eigenvectors.")
  • Caption of Figure 8.10: The operating region is light gray and the continuous operating region is dark gray.
  • Exercise 8.6(a): The expression has the indices switched; the correct expression is .
  • Exercise 8.7: The expression should be written:

Chapter 10

  • Equation (10.4) should read (the plus sign in the book should be a minus sign).

Chapter 11

  • In the displayed equation after Equation (11.18), the vector is a six-vector. The bottom three elements are written correctly, but the top three elements, an angular velocity, are written instead in their 3x3 form.
  • In Equation (11.33), the right-hand side should be zero ().
  • Figure 11.24, the Robonaut 2 series elastic actuator, 4th sentence of the caption: The words "outer" and "inner" should be switched, so the new sentence reads "The inner ring of hole mounts connects to the harmonic gearhead output, and the outer ring of hole mounts is the output of the SEA, connecting to the next link."

Appendix C

  • Section C.3, Equation (C.5): All instances of should be replaced by .
  • In Equation (C.12), two instances of should be replaced by .

Minor typos, etc., no danger of misunderstanding

Chapter 1

  • (online version only) Description of Chapter 6: "jont positions" should be "joint positions."

Chapter 2

  • Chapter 2.2.2, Example 2.3: "Substituting" is misspelled.

Chapter 5

  • Figure 5.15(b): The circular arrow indicating the rotation of joint 3 is slightly misplaced.
  • Exercise 5.25: This problem instructs you to use the space Jacobian, so you should use it for the manipulability ellipsoids in this problem (even though it is generally preferred to use the body Jacobian for manipulability ellipsoids).

Chapter 6

  • (online version only) Figure 6.7: should be (five times) and should be (one time).

Chapter 7

  • (online version only) Last line of first paragraph of Chapter 7.1: "valuees" should be "values."
  • Just below caption for Figure 7.8: There is an extraneous dot.

Chapter 8

  • (online version only) Chapter 8.1.1, last paragraph: is improperly typeset.

Chapter 12

  • Caption of Figure 12.14, second-to-last sentence: "rotation if possible" should be "rotation is possible."

A partial list of errata contributors

Thanks to the following people who provided corrections, starting from the preliminary version of the book posted in October, 2016:

H. Andy Nam, Eric Lee, Yuchen Rao, Chainatee Tanakulrongson, Mengjiao Hong, Kevin Cheng, Jens Lundell, Elton Cheng, Michael Young, Jarvis Schultz, Logan Springgate, Sofya Akhmametyeva, Aykut Onol, Josh Holcomb, Yue Chen, Mark Shi, AJ Ibraheem, Yalun Wen, Seongjae Jeong, Josh Mehling, Felix Wang, Drew Warren, Chris Miller, Clemens Eppner, Zack Woodruff, Jian Shi, Jixiang Zhang, Shachar Liberman, Will Wu, Dirk Boysen, Awe Wang